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| APPLICATION NOTE TEA2260/TEA2261 HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S SUMMARY I I.1 I.2 I.3 I.4 I.5 II II.1 II.2 II.3 II.4 II.5 II.6 II.7 II.8 II.8.1 II.8.1.1. II.8.1.2. II.8.1.3. II.8.2 II.8.2.1. II.8.2.2. II.9 III III.1 III.2 III.2.1 III.2.1.1 III.2.2 III.2.2.1 III.2.2.2 III.2.2.3 III.2.3 III.2.4 III.2.5 III.2.6 III.2.7 III.2.8 III.2.9 III.3 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . MASTER SLAVE MODE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BURST MODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OPERATION OF MASTER SLAVE POWER SUPPLY IN TV APPLICATION . . . . . . . . SECONDARY REGULATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PRIMARY REGULATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CIRCUIT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VOLTAGE REFERENCE AND INTERNAL VCC GENERATION. . . . . . . . . . . . . . . . . . . OSCILLATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ERROR AMPLIFIER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PULSE WIDTH MODULATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SOFT START OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . BURST GENERATION IN STAND BY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IS LOGIC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SAFETY FUNCTIONS : DIFFERENCES BETWEEN TEA2260 AND TEA2261. . . . . . . I max . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . First threshold VIM1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Second threshold VIM2 for TEA2260 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Second threshold VIM2 for TEA2261 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Logical block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Logical block for TEA2260 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Logical block for TEA2261 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . OUTPUT STAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TV APPLICATION 120W 22O VAC 16KHz SYNCHRONIZED . . . . . . . . . . . . . . . . . . . CHARACTERISTICS OF APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CALCULATION OF EXTERNAL COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transformer calculation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transformer specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Switching transistor and its base drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Current limit calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Snubber network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Base drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Oscillator frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Regulation loop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Overload capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soft start capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Feedback voltage transformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Start up resistor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . High voltage filtering capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ELECTRICAL DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2 2 2 2 6 8 9 10 10 12 12 13 13 14 15 16 17 18 18 18 18 19 19 20 20 20 21 22 22 22 23 24 25 25 26 26 26 27 28 29 1/33 AN376/0694 HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S SUMMARY (continued) IV IV.1 IV.2 IV.3 V V.1 V.2 V.3 V.4 TV APPLICATION 140W 220 VAC 32kHz SYNCHRONIZED . . . . . . . . . . . . . . . . . . . . APPLICATION CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TRANSFORMER CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ELECTRICAL DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TV APPLICATION 110W 220 VAC 40kHz REGULATED BY OPTOCOUPLER . . . . . . FREQUENCY SOFT START . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . APPLICATION CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TRANSFORMER SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ELECTRICAL DIAGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 32 32 32 33 34 34 34 34 35 I - INTRODUCTION The TEA2260/61 is an integrated circuit able to drive a bipolar transistor directly with an output base current up to 1.2A. So the TEA 2260/61 covers a wide range of application from 80W to more than 200W with all safety requirements respected. The high performances of the regulation loop provide a very low output power due to an automatic burst mode. The TEA2260/61 can be used in a MASTER SLAVE STRUCTURE, in a PRIMARY REGULATION or a SECONDARY REGULATION. The TEA 2260/61 is very flexible and high performance device with a very large applications field. The only difference between TEA2260 and TEA2261 concerns security functions (see paragraph II.8) I.1 - Master Slave Mode (Figure 1) In this configuration the master circuit located on the secondary side, generates PWM pulses used for outputvoltage regulation. These pulses are sent via a feedback transformer to the slave circuit (Figure 1). In this mode of operation, the falling edge of the PWM Signal may be synchronized with an external signal. By this way the switching off time of the power transistor, which generates lot of parasites, can be synchronized on the line flyback signal in TV applications. An other advantage of the MASTER SLAVE STRUCTURE is to have a very good regulation not depending of the coupling between transformer primary and secondary windings, which allows the use of low cost switch mode transformers. I.2 - Burst Mode (Figure 2) During start-up and stand-by phases, no regulation pulses are provided by the master circuit to the slave circuit. The slave circuit operates in primary regulation mode. When the output power is very low the burst mode is automatically used. This operating mode of the SMPS effectively provides a very low output power with a high efficiency. The TEA2260/61 generates bursts with a period varying as a function of the output power. Thus the output power in burst mode can varied in a wide range from 1W to more than 30W. I.3 - Operation of Master Slave Power Supply in TV Application The system architecture generally employed is depicted in Figure 3. On the secondary side a micro controller is connected to the remote control receiver which generates control signal for the standby and normal modes of operation (Figure 4). - In stand-by mode, the device power consumption is very low (few watts). The master circuit does not send pulses and hence the slave circuit works in primary regulation and burst mode. - In the normal mode, the master circuit provides the PWM signal required for regulation purposes. This is called MASTER SLAVE MODE. The master circuit can be simultaneously synchronized with the line flyback signal. - Power supply start-up. As soon as the VCC(start) threshold is reached, the slave circuit starts in continuous mode and primary regulation as long as the nominal output voltages are not reached. After this start-up phase the microcontroller holds the TV Set in stand-by mode or either in normal mode. 2/33 HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Figure 1 Sync. Pulses PWM Signal SLAVE CIRCUIT MASTER CIRCUIT Pulse Input Figure 2 : Burst Mode Operation Burst Period typ ~ 30ms ~ Switching Period COLLECTOR CURRENT ENVELOP DETAIL OF ONE BURST 3/33 376-02.EPS 376-01.EPS Base Current 4/33 AUDIO OUTPUT STAGE Muting Control R P1 Synchronization SCANNING DEVICE Remote Stand-by P2 C VOLTAGE REGULATOR Remote Stand-by V CC Figure 3 : TV Application System Diagram MAINS INPUT HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S TEA2260/61 TEA5170 P V CC INFRA-RED RECEIVER PWM P 1 : Output voltage adjustement in normal mode Small signal primary ground Power primary ground Secondary ground (isolated from mains) P 2 : Output voltage adjustement in stand-by 376-03.EPS TEA2260/61 VCC voltage t VCC(START) VCC(STOP) Collector current envelop t Figure 4 : System Description (waveforms) Output voltage t TEA5170 Output voltage envelop t 1 1 2 P supply voltage 2 Stand-by control voltage t1 Stand-by t Normal operation t2 Stand-by Start-up HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S * t and t 1 2 : commands issued by P 5/33 376-04.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S I.4 - Secondary Regulation (Figures 5 and 6) In this configuration the TEA2260/61 provides the regulation through an optocoupler to ensure good accuracy. The advantage of this configuration is the avaibility of a large range of output power variation (e.g 1W to 110W). Figure 5 : TV Application System Diagram INFRA-RED RECEIVER Small signal primary ground Power primary ground Secondary ground(isolated from mains) P : Output voltage adjustement This feature is due to the automatic burst mode (see paragraph II.6). The structure in a TV Set is simpler than the MASTER SLAVE STRUCTURE because the power supply switches from normal mode to burst mode automatically as a function of the output power. Remote Stand-by Muting Control P P VOLTAGE REGULATOR SCANNING DEVICE AUDIO OUTPUT STAGE R MAINS INPUT C TEA2260/61 VCC VCC 6/33 376-05.EPS TEA2260/61 VCC voltage t VCC(START) VCC(STOP) Collector current envelop t Figure 6 : System Description (waveforms) Output voltage t Stand-by voltage envelop t 1 P supply voltage t t1 Stand-by Normal operation t2 Stand-by Start-up HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S * t and t 1 2 : commands issued by P 7/33 376-06.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S I.5 - Primary Regulation (Figure 7) In this configuration the TEA2260/61 provides the regulation through an auxilliary winding. This structure is very simple but the accuracy deFigure 7 : TV Application System Diagram INFRA-RED RECEIVER pends on the coupling between the transformer primary and secondary winding. Due to the automatic burst mode the output power can vary in a large range. Remote Stand-by Muting Control P VCC V CC R C TEA2260/61 P P : Output voltage adjustement MAINS INPUT Small signal primary ground Power primary ground Secondary ground (isolated from mains) VOLTAGE REGULATOR SCANNING DEVICE AUDIO OUTPUT STAGE 8/33 376-07.EPS Figure 8 S 7 15 15.7V VCC MONITORING OVERVOLTAGE PROTECTION VREF (2.49V) 7.4V 10.3V + INTERNAL BIAS VCC 16 V+ ERROR AMPLIFLIER + II - CIRCUIT DESCRIPTION Figure 8 shows the integrated functions. VREF 2.49V -1 MODULATOR LOGIC PRIMARY PULSES IS LOGIC LOGIC PROCESSOR REGULATION PULSES - + MODULATORS AUTOMATIC BURST GENERATION REPETITIVE OVERLOAD PROTECTION DEMAGNETIZATION SENSING + 45A + 0.15V 2.55V SECONDARY PULSE 10A + TON(Max.) (60%) SOFT-START OSCILLATOR - 9 10 11 1 2 8 HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S C1 R0 C0 IS IN C2 376-08.EPS - POSITIVE OUTPUT STAGE VCC - 2A (Max.) + 1.2A (Max.) NEGATIVE OUTPUT STAGE CURRENT LIMITATION + E6 - 14 OUT - + 0.6V - 0.9V 3 4 5 12 13 I MAX GND 9/33 HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S The circuit contains 8 blocks : - Voltage reference and internal VCC generation. - RC oscillator - Error amplifier - Pulse width modulator (PWM) - "Is logic" for transformer demagnetization checking. - Current limitation sub-unit (IMAX) - Logical block. - Output stage. II.1 - Voltage Reference and Internal VCC Generation (Figure 9) This block generates a 2.5V typ. voltage reference valid as soon as VCC exceeds 4V. It is not directly accessible externally but is transmitted to other blocks of the circuit. Figure 9 : Voltage Reference Block Principle This block also generates an internal regulated VCC, VCC(int), the nominal value of which is 5V. VCC(int) supplies the circuit when Vcc is higher than VCC(start) (10.3V typ.). This allows the circuit to achieve a good external VCC rejection, and to provide high performance even with large VCC supply voltage variations. This block also generates initialization and control signals for the logical block. It also contains the VCC(Max.) comparator (typ threshold 15.7V). II.2 - Oscillator (Figures 10 and 11) The oscillator determines the switching frequency in primary regulation mode. Two external components are required : a resistor RO and a capacitor CO. The oscillator generates a sawtooth signal, which is available on Pin 10. Figure 10 : Operating Principle 10/33 376-10.EPS 376-09.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Figure 11 : Sawtooth available accross CO CO capacitor is charged with a constant current. The current is fixed by RO which is supplied by voltage VREF. Ich = 2.5 RO Wh e n t he v o lt a g e a cros s CO re a c he s 2 x VCCint (typ 3.33V), Q Transistor conducts and 3 CO is quickly discharged into an 2k (typ) internal r es ist or. Wh e n t he vo lt ag e rea c he s Figure 12 : Frequency as a Function of RO and CO 1/3 x VCCint (typ 1.66V), the discharge is stopped, and the linear charge starts again. Theoretical values of T,T1 and T2 as function of RO and CO : T = CO (0.69 x RO + 1380) T1 = RO x CO x 0.69 T2 = CO x 2000 x 0.69 = CO x 1380 Due to the time response of comparators and normal spread on thresholds values, the real values ofT1 and T2 may be slightly different, compared with these theoretical values (see Figure 12). 11/33 376-12.EPS 376-11.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S II.3 - Error Amplifier (Figure 13) It is made of anoperational amplifier. The open loop gain is typically 75dB. The unity gain frequency is 550kHz (typ). An internal protection limits the output current (Pin 7) at 2mA in case of shorted to ground. Figure 13 The TEA2260/61 actually integrates two PWM : - A main PWM generates a regulation signal () by comparing the error signal (inverted) and the sawtooth. - An auxiliary PWM generates a maximum duty cycle conduction signal (), by comparing the sawtooth with an internal fixed voltage. Furthermore, during the starting phase of the SMPS, in association with an external capacitor, this PWM generates increasing duty cycle, thus allowing a "soft" start-up. - A logic "AND" between signals () and () provides the primary regulator output signal TA. 376-13.EPS II.4 - Pulse Width Modulator (PWM) (Figure 14) The pulse width modulator consists of a comparator fed by the output signal of the error amplifier and the oscillator output. Its output is used to generate conduction signal. Output and inverting input are accessible thus giving high flexibility in use. The non-inverting input is not accessible and is internally connected to VREF (or0.9VREF in burst mode - see paragraphII.6) Before driving the pulse width modulator (PWM) and in order to get the appropriate phase, the error amplifier is followed by an inverter. Figure 14 12/33 376-14A.EPS / 376-14B.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Figure 15 the voltage reference is applied to the non- inverting input of the error amplifier. When output power decreases as the minimum conducting time of the power transistor is reached, the output voltage tends to increase. Consequently the error signal applied to the PWM becomes higher than the sawtooth. This is detected by a special logic and the voltage applied to the non inverting input becomes VREF = 0.9 x 2.5 = 2.25V typically. Consequently the regulation loop is in an overvoltage equivalent state and the output pulses disappear. The output voltage decreases and when it reaches a value near 0.9 times the normal regulation value , the voltage applied to the non inverting input is switched again to the normal value VREF = 2.5V. Pulses applied to the power transistor reappear, the output voltage increases again, and so on... A relaxation operation is obtained, generating the burst. Futhermore, to avoid a current peak at the beginning of each burst, the soft-start is used at this instant. Advantages of this method - improved power supply efficiency compared with traditional systems, for low power transmission. - automatic burst-mode continuous mode transition, as a function of the output power. - high stand-by power range. - burst frequency and duty cycle adjustable with external components to the circuit. II.5 - Soft Start Operation (Figure 16) From t1 to t2, there is no output pulse (pin 14) and C1 is charged by a 180A current (typically). When C1 voltage reaches 1.5V (typically), output pulses appear and the charge current of C1 is divided by 20 (9A typically), then the duty cycle increases progressively. When C1 voltage reaches 2.7V (typically), the soft-starting device ceases to limit the duty cycle, which may reach 60%. Under established conditions C1 voltageis charged to 3.1V (typically) II.6 - Burst Generation in Stand By (primary regulation mode) When the SMPS output power becomes very low, the duty cycle of the switching transistor conduction becomes also very low. In order to transmit a low average power, while ensuring correct switching conditions to the power transistor, a "burst" system is used for energy transmission in stand by mode. Principle For a medium output power (e.g. more than 10W), Figure 16 : C1 Voltage (Pin 9) 376-15.EPS 13/33 376-16.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S II.7 - IS Logic (Figure 17) During the transition from the "stand-by" mode to the "normal operating" mode, conduction pulses generated by the secondary regulator occur concurrently with those from the primary regulator. These pulses are non-synchronous and this may be dangerous for the switching transistor. For example if the transistor is switched-on again during the overvoltage phase, just after switching-off, the FBSOA may not be respected and the transistor damaged. To solve this problem a special arrangementchecking the magnetization state of the power transformer is used. The aim of the IS Logic is therefore to monitor the primary regulation pulses (TA) and the secondary regulation pulses (Pin 2), and to deliver a signal TB compatible with the power transistor safety requireFigure 17 : IS Logic Principle Schematic ments. The IS Logic block comprises mainly two D flipflops. When a conduction signal arrives, the corresponding flip-flop is set in order to inhibit a conduction signal coming from the other regulation loop. Both flip-flops are reset by the negative edge of the signal applied to the demagnetizationsensinginput (Is Pin 1). Note :The demagnetization checking device just described is only active when there are concurrently primary and secondary pulses, which in practice only occurs during the transient phase from Stand-by mode to normal mode. When the power supply is in primary regulation mode or in secondary regulationmode, the demagnetization checking function is not activated. Figure 18 14/33 376-18.EPS 376-17.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S II.8 - Safety Functions : Differences between TEA2260 and TEA2261 TEA2260 Concerning the safety functions, VCC(max) (overvoltage detection) VIM1, VIM2 (overcurrent detection) the TEA2260 uses an internal counter which is incremented each time VCCstop is reached (after fault detection) and try to restart. After 3 restarts with fault detection the power supply stops. But in certain cases where the TV set is supplied for a long time, without swich off, the power supply could Figure 19 : TEA2260 Safety Functions Flowchart stop (cases of tube flashes). In this case it is necessary to switch off the TV set and swich on again to reset the internal counter. TEA2261 The safety detections are similar to TEA2260 for VCC(max) (overvoltage detection) VIM1, VIM2 (overcurrent detection),but each time a fault detection is operating the C2 capacitor is loaded step by step up to 2.6V, (case of long duration fault detection) and the power supply stpos. To discharge C2 capacitor it is necessary to switch off the TV set and to switch on again and the power supply starts up. S.M.P.S. starting First threshold reached VIM1 N Y Y Second threshold reached VIM2 N Pulse by pulse current limiting C 2 charged VC2 < 2.6V VCCmax reached N Normal operating C 2 discharged Restart number = 3 Y Reset C 2 discharged Y N Definitive stopping Y Y N S.M.P.S. stopping VCC stop reached N=N+1 N 15/33 376-19.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Figure 20 : TEA2261 Safety Functions Flowchart S.M.P.S. starting First threshold reached VIM1 N Y Second threshold reached VIM2 Y Y C2 charged S.M.P.S. stopped N VCC max reached N Normal operating C 2 discharged Pulse by pulse current limiting C2 charged VC2 < 2.6V VC2 < 2.6V Y N Y N Definitive stopping Y 16/33 376-21.EPS II.8.1. I Max (power transistor current limitation) The current is measured by means of a resistor inserted in the emitter of the power transistor. The voltage obtained is applied on Pin 3 of the TEA2260/61. The current limitation device of the TEA2260/61 is a double threshold device. For the first threshold, there isno difference between the two devices,only for the second threshold. Figure 21 376-20.EPS Reset C2 discharged N HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S II.8.1.1 - First threshold : VIM1 (typical value) Figure 22 : Current Limitation Schematic Principle. First Threshold Part. Two actions are carried out when the first threshold is reached - The power transistor is switched-off (pulse by pulse limitation). A new conduction pulse is necessary to switch-on again. - The C2 capacitor, which is continuously discharged by Idisch current (10A typically), is charged by the current Ich - I disch (45A - 10A = 35A typically), until the next conduction pulse. The capacitor C2 is charged as long as an output overload is triggering the first current limitation threshold. When the voltage across C2 reaches the threshold VC2 (typically 2.55V), output pulses (pin 14) are inhibited and the SMPS is stopped. A restart may be obtained by decreasing Vcc under the VCC(stop) threshold to reset the IC. If the output overload disappears before the voltage across C2 reaches VC2, the capacitor is discharged and the power supply is not turned off. Due to this feature, a transient output overload is tolerated, depending on the value of C2 (see III.2.5). Figure 23 : Example of First Current Limitation Threshold Triggering 17/33 376-23.EPS 376-22.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S II.8.1.2 - Second current limitation threshold (VIM2) for TEA2260 In case of hard overload or short circuit, despite the pulse by pulse current limitation operation, the current in the power transistor continues to increase. If the second threshold VIM2 is reached, the power supply is immediately turned off and the internal counter is incremented. After 3 restarts, the power supply is definitively stopped.Restart is obtained by decreasing VCC below VCC(stop), as in the case of stopping due to the repetitive overload protection triggering. II.8.1.3 - Second current limitation threshold (VIM2) for TEA2261 For this device, if the second threshold is reached, the power supply is turned off, C2 is charged and a new start-up is authorized only if VC2 < 2.6V. II.8.2 - Logical Block This block receives the safety signals coming from different blocks and inhibits the conduction signals when necessary. II.8.2.1 - Logical block for TEA2260 TB is the conduction signal (primary or secondary)coming from th e Is logical block. is the conduction signal transmitted to the output stage. is the output signal of the first current I1 limitation threshold comparator. It is memorized by the flip-flop B1. I2 is the output signal of the second c u rre n t limit a t io n t h re s ho ld comparator VC2 is the output signal of the comparator checking the voltage across C2. is the signal coming from VCC VCC (Max.) checking comparator. These three signals VC2, I2, Vcc(max) are memorized by B2. In case of B2 flip-flop setting (I2 or VC2 or Vcc(max) defect) the current consumption on VCC increases. This function allows to decrease the Vcc voltage until VCC(stop). After this the current consumptionon Vcc decreases to ICC(start) and a new start up is enabled. The VCC(Off) signal comes from the comparator checking VCC. A counter counts the number of VCC(off) establishment. After four attempted starts of the power supply the output of the circuit is inhibited. To reset the circuit it is necessary to decrease VCC below 5.5V typically. In practice this means that the power supply has to be disconnected from the mains. TC Figure 24 : TEA2260 Simplified Logical Block Diagram 18/33 376-24.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S II.8.2.2 - Logical block for TEA2261 Figure 25 I2 VCC (Max.) VCC (off) OR S Q AND R Q TC TB S Q I1 OR R Q 2.6V S Q 8 R RESET VCC(off) is a signal coming from a comparator checking VCC. When VCC > VCC(stop),VCE(off) is high. VCC(max) is a signal coming from a comparator checking VCC. When VCC > VCC(max),VCC(max) is high. I1 is a signal coming from the first current limitation threshold comparator. When Imax x RSHUNT > VIM1, I1 is high. I2 is a signal coming from the second current limitation threshold comparator. When Imax x RSHUNT > VIM2,I2 is high. Figure 26 TB is the conduction signal coming from the error ampliflier system. TC is the output signal transmitted to the output stage. II.9 - Output Stage The output stage is made of a push-pull configuration : the upper transistor is used for power transistor conduction and the lower transistor for power transistor switch-off. A capacitive coupling is recommanded in order to provide a sufficient negative base current through the power transistor . 19/33 376-26.EPS 376-25.EPS C2 HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Figure 27 : Typical Voltage Drops of Output Transistor versus Current Important remark : Due to the internal output stage structure, the output voltage (Pin 14) must never exceed 5V. This condition is respected when a bipolar transistor is driven. Note that Power-MOS transistor drive is not possible with the TEA2260/61. III - TV APPLICATION 120W - 220 VAC - 16kHZ SYNCHRONIZED ON HORIZONTAL DEFLECTION FREQUENCY General structure and operational features of this power supply were outlined in section I. The details covered below apply to a power supply application using the master circuit TEA5170. (refer to TEA5170 data sheet and TEA5170 application note "AN088" for further details). III.1 - Characteristics of Application - Discontinuous mode Flyback SMPS - Standby function using the burst mode of TEA2260/61 - Switching Frequency - Normal mode : 15.625 kHz (synchronized on horizontal deflection frequency) - Standby mode : about 16kHz - Nominal mains voltage : 220 VAC Mains voltage range : 170 VAC to 270 VAC - Nominal output power : 120W - O u t p u t p o wer ra n ge in n orma l mo d e 14W < PO < 120W - O u t p u t po wer ra n ge in st a n db y mo de 1W < PO < 25W - Efficiency - Normal mode : 85% (under nominal conditions) - Stand by mode : 45% - Regulation performance on high voltage output : 140 VDC 20/33 - - 0.3% versus mains variations of 170 VAC to 270 VAC (POUT : 120W) - 0.5% versus load variations of 14W to 120W (Vin = 220 VAC) Overload protection and complete shut down after a predetermined time interval. Short circuit protection. Open load protection by output overvoltage detection Complete power supply shut-down after 3 restarts resulting in the detectionof a fault condition. Complete power supply shut-down when VC2 reaches 2.6V for TEA2261. III.2 - Calculation of External Components Also refer to TEA5170 application note "AN-088" for calculation methods applicable to other power supply components. The external components to TEA2260/61 determine the following parameters : - Operating Frequency in primary regulation - Minimum conduction time in primary regulation - Soft start duration - overload duration - Error amplifier gain and stand-by output voltage - Base drive of the switching transistor - Primary current limitation Ideal values - Free running Frequency in stand-by mode : 16kHz - Ton(min) duration : 1s - Soft start duration : 30ms - Maximum overload duration : 40ms - Error amplifier Gain : 15 - Maximum primary current depends on the transformer specifications 376-27.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S III.2.1 - Transformer calculation The following important features must be considered to calculate the specifications of the transformer : - Maximum output power : 120W - Minimum input voltage : - 220 VAC - 20% Vin(min) = 210 VDC with 40V ripple on the high voltage filtering capacitor - Switching Frequency : 15.625kHz - Maximum duty cycle : 0.45 - Output voltages : + 140V - 0.6A + 14V - 0.5A + 25V - 1A + 7.5V - 0.6A + 13V - 0.3A Maximum primary current TON(max) T : efficiency of the power supply 0.80 < < 0.85 x VIN(min) x Figure 28 IP(max) = 2 x Primary inductance of the transformer VIN(min) x TON(max) LP = IP(max) Transformer ratio ns (VOUT + VD) x TDM = np VIN(min) x TON(max) Reflected voltage VR = 1 T -1 x VIN(min) TON(max) POUT Overvoltage due to the leakage inductance IP(max) Lf x VPEAK = 2 C with : Lf = leakage inductance of the transformer 0.04 x Lp < Lf < 0.10 x Lp C = capacitor of the snubber network (see III.2.2.2) 21/33 376-28A.EPS / 376-28B.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Numerical application To determinate the specifications of the transformer, it is necessary to make a compromise between a maximum primary current and a maximum voltage on the transistor : - To minimize the maximum primary current T ON(max) with 0.4 < < 0.5 T - To minimize the maximum voltage on the transistor during the demagnetization phase. TON(max) < 0.4 0.3 < T When the output power of the power supply is greater than 100W it is better to minimize the maximum primary current because the current gain Bf = IC / IB of bipolar transistor is 1.5 < Bf < 6 TON(max) Choice : < 0.45 T IP(MAX) = 2 x POUT 2 x 120 = 3A = TON(MAX) 0.85 x 210 x 0.45 x VIN(MIN) x T III.2.1.1 - Transformer specification - Reference : OREGA - SMT5 - G4467-03 - Mechanical Data : - Ferrite : B50 - 2 cores : 53 x 18 x 18 (mm) THOMSON-LCC - Airgap : 1.7 mm - Electrical Data : Figure 29 3 13 20 19 14 6 17 9 22 7 21 376-29.EPS Wind ing nP nAUX n2 n3 n4 n5 Pin 3-6 7-9 19-13 19-20 14-17 22-21 Inductance 1.95H 8.1H 770H 8.2H 4.2H 31.7H LP = VIN(MIN) 210 x TON(MAX = x 0.45 x 64 10-6 = 1.95mH ) IP(MAX) 3 1 T VR = TON(MAX) -1 x VIN(MIN) = 1 x 210 = 172V 1 -1 0.45 VPEAK will be calculated with the snubber network determination (see II.2.2.2.1) III.2.2 - Switching transistor and its base drive III.2.2.1 - First current limitation Figure 30 : Current Limitation Note : in current limitation TIBon < TON 22/33 376-30A.EPS / 376-30B.EPS / 376-30C.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S The current measurement is IE = IB + IC The maximum collector current calculated in III.2.1 is IC(Max.) = 3A (a switching transistor SGSF344 may be chosen) IC = 3.5 The current gain is: Bf = Figure 31 IB+ The current limitation is : VIN(min) ) + IB+ LP with : TS = storage time of the switching transistor (typ 3s) and VIM1 = first threshold of current measurement (typ 0.6 v) VIM1 RSHUNT = IE(max) IE(max) = IP(max) - (TS x Numerical application VIN(min) IE(max) = IP(max) - (TS x ) + IB+ LP IE(max) = 3 - (3 10-6 x RSHUNT = VIM1 IE(max) = 3.255 210 ) + 0.85 = 3.55A 1.95 10-3 0.6 = 0.169 III.2.2.2 - Snubber network A R.D.C network is used to limit the overvoltage on the transistor during the switching off time. When the transistor is switched off, the capacitor is charged directly through the diode. When the transistor is switched on, the capacitor is discharged through a resistor. IP(max) x tf - C= VCEO 2x 3 - 3 x R x C = Ton(min) (to discharge the capacitor C by the correct amount) - Maximum power dissipated in R : 1 P = x C x (VIN(max) + VR) 2 x F 2 Numerical application (with SGSF 344 transistor) with : IP(Max.) = 3A - VIN(Max.) = 370 VDC tf = 0.3s - VR = 172V VCEO = 600V - F = 16kHz TON(Min.) = 4s IP(max) x tf 3 x 0.3 10-6 = C= = 2.25nF 600 VCEO 2x 2x 3 3 TON(min) 4 10-6 = 560 = 3xC 3 x 2.25 10-9 1 P = x C x VIN(max) + VR) 2 x F 2 1 P = x 2.25109 x (370 + 172)2 x 16103= 5.29W 2 In the final application a value of 2.7nF is chosen to decrease the overvoltage on the transistor in short circuit condition. R= 23/33 376-31A.EPS / 376-31B.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S III.2.2.2.1 - Overvoltage due to the leakage inductance (See. III.2.1) The capacitor C of the snubber network influences the overvoltage due to the leakage inductance. Vpeak = IC(max) Figure 32 2 Lf C Numerical application with : Lf = 0.08 x Lp = 0.08 x 1.9 10 -3 = 152H Vpeak 3 x 2 152 106 2.25 109 = 390V so VCE(Max.) = VIN(Max.) + VR + Vpeak = VCE(Max.) = 370 + 172 + 390 930V 376-32A.EPS / 376-32B.EPS III.2.2.3 - Base drive The output stage of the TEA2260/61 works in saturation mode and hence the internal power dissipation is very low. R1 = VCC+ - VP - VZ - VBE IB+ Numerical application 13 - 0.9 - 3 - 0.6 IC 3 10 in this case the current gain, BF = = = 3.5 but it is recomR1 = 0.85 IB 0.85 manded to verify the VCE sat dynamic behaviour on the transistor as follows : see Figure 33 Figure 33 Ideal value : 1V VCEsat + VD 2V 376-33A.EPS / 376-33B.EPS Remark : The mains of the TEA2260/61 must be provided through an isolation transformer for this measurement 24/33 HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S III.2.3 - Oscillator frequency The free running frequency is given on II.2. The typical value of minimum conduction time T on(min) on the output of the TEA2260/61 is given by: Ton(min) = 1040 x CO Note : the minimum conduction time TON(min) on the transistor is longer due to the storage time. Figure 34 Numerical application FO = 16kHz CO is chosen at 1nF so TON min on the TEA2260/61 = 1s 1 - 1.57 103 RO = FO x CO x 0.66 1 RO = - 1.57 103 3 -9 16 10 x 1 10 x 0.66 RO = 93 K RO = 100k is chosen. Note : Fo is chosen relatively low to avoid magnetization of the transformer during the start-up phase. III.2.4 - Regulation loop In stand by mode the error amplifier of the TEA2260/61 carries out the regulation. - The R.C. filter is necessary to avoid the peak voltage due to the leakage inductance. The time constant = RC is about 30s < R.C. < 150s as a function of the transformer technology. - To achieve a stable behaviour of the regulation loop and to decrease the ripple on the output voltage in stand by mode the time constant should be approximately : ROUT x COUT (R1 + R2 + R3) x C 15 with : COUT (filtering output capacitor) and ROUT (load resistor on the output in stand by mode) - To ensure a stable behaviour in stand-by mode the amplifier gain is choosen to : R4 G= 15 R2 + R3 Figure 35 Calculation of R, R1, R2, R3, R4 a) The resistor R is given by R= C C choosen between 1F < C < 10F = 80s is chosen C = 2.2F is chosen 25/33 376-35.EPS 376-34.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Numerical application 80 10 = = 36 C 2.2 10-6 b) The resistors R1, R2, R3 are given by COUT x ROUT R1 + R2 + R3 15 x C with : Vref : reference voltage of the error amplifier Vref = 2.5V Vcc(stand by) : Vcc voltage in stand by mode. Vcc(stand by) = 0.9 x Vcc (in normal mode) SO R = Numerical application with : Vcc = 13V Vref = 2.5V Rout = 2k on output 135 V Cout = 100F on output 135 V C = 2.2F R1 + R2 + R3 -6 Figure 36 : Load of Overload Capacitor C OUT x ROUT 100 10-6 x 2 103 = = 6k 15 x C 15 x 2.2 10-6 Numerical application with : maximum overload time = 40 ms the longer delay time is obtained when Ton = Ton(max) T - Ton(max) Toverload C2 = (( x ICH) - IDISCH) x 2.5 T C2 = (0.55 x 45 10-6 - 10 10-6 40 10-3 220nF 2.5 Note : in practice, the overload capacitor value must be greater than the soft start capacitor (C2 C1) to ensure a correct start up phase of the power supply. III.2.6 - Soft start capacitor Refer to paragraph II.5 for the soft start function explanation. The soft start duration is given by : (2.7 - 1.5) x C1 TSOFTSTART = 9 10-6 C1= 7.5 10-6 x TSOFTSTART Numerical application with : Tsoft start = 30 ms C1 = 7.5 10-6 x 30 10-3 = 220 nF III.2.7 - Feed back voltage transformer A feedback voltage transformer is used to send information from the secondary circuit (master circuit) to the primary circuit (slave circuit). This transformer is needed to provide an electric insulation between primary and secondary side. The feedback input of TEA2260/61 is fed with logic level (threshold 0.9V) It is necessary to have the same waveform on the primary side as on the secondary side. R2 + R3 = (R1 + R2 + R3) x R2 + R3 = 6 103 x VREF VCC(stand by) 2.5 = 1.28k 0.9 x 13 values choosen : R2 potentiometer resistor of 1k R3 fixed resistor 1k R1 = (R1+ R2 + R3) - (R2+ R3) R1 = 6k - 1.28k = 4.7k c) The resistor R4 is given by R4 15 x (R2 + R3) Numerical application R4 15 x (R2 + R3) 15 x (1.28 103) 18k III.2.5 - Overload capacitor When an overload is detected with the first threshold VIM1 the capacitor C2 (pin 8) is charged until the end of the period as shown in figure 33. So the average load current is given by : T - TON IC2 = x ICH - IDISH T the threshold to cut off the TEA2260/61 power supply is 2.5V typically and hence the delay time before overload detection is given by : 2.5 x C2 Toverload = T - TON x ICH) - IDISCH ( T 26/33 376-36.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S Figure 37 Figure 38 For this reason the time constant must be higher than the maximum conduction time in normal mode. Hence the primary inductance Lp must be calculated as follows : Lp > 3.R.Ton(max) Numerical application with : TON(max) = 28s R = 270 Lp > 3 x 270 x 28 10-6 = 22mH a) When the TEA5170 is used VIN = 7V VS(min) ns = np TON(max) VIN x (1 - ) T ns 1.5 = 0.389 = np 7 x (1 - 0.45) b) When the TEA 2028 is used VIN = 12V ns 1.5 = = 0.227 np 12 x (1 - 0.45) Note : The R1.C1 filter is used to damp oscillation on the secondary side of the feedback transformer. The time constant R1 x C1 0.1s. III.2.8 - Start up resistor After switching on the power supply the filtering capacitor on VCC of TEA2260/61 is charged through a resistor connected to the mains input voltage. Do not connect this resistor to the high voltage filtering capacitor because there is enough energy in this capacitor to cause three attempted restarts and to cut off the TEA2260/61 on fault detection when the power supply is switched off. Hence it is recommended to connect the start-up resistor as follows : 376-37.EPS Start up delay time IMOY = 2 x VIN AC(min) x RST VCC START xC IMOY - ICC START Start-up delay time = Tst = RST = x (C x 2 x VIN AC(min) VCC START ) + ICC START TST Power dissipated in start up resistor P= VIN AC(max) 2 2 . RST Numerical application with : start up delay time = 1s VIN(max) = 370V DC (VIN AC(max) = 265V) VIN AC(min) = 175V Vccstart = 10.3V Iccstart = 0.7mA C = 220F 2 x 175 = 26k RST = -6 x (220 10 x 10.3 + 0.7 10-3) Value choosen = 22k Power dissipated (265)2 P= = 1.6W 2 x 22 103 27/33 376-38.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S III.2.9 - Determination of high voltage filtering capacitor Figure 39 Hypothesis : V : ripple on the filtering voltage VIN.AC(min) : minimal value of A.C. input voltage T : period of the mains voltage Pout : output power of the power supply : efficiency of the power supply V + ArcSin(1 - ) 2 VIN AC(min) x2 POUT T x C= x VIN AC(min) x 2 2 Numerical application V = 40V VIN AC(min) = 170 VAC T = 20ms POUT = 120W = 0.85 20 10 C= 2 -3 x 2 + ArcSin(1 - 40 x 250 40 250 ) x 120 0.85 = 115F value choosen : C = 120s 28/33 376-39A.EPS / 376-39B.EPS Figure 40 170 VAC 3 4 x 1N4007 13 P1 20 12V BY218-600 270 VAC 135V III.3 - Electrical Diagram 120F 385V PLR811 100F 250V 120k 2.2k 7.5V 1000F 25V BC547C 22k 2W 47k 4.7k 1N4148 36 6 2.2 /0.5W 19 14 BY218-100 470F 25V 1k P2 9 BA157 18k 1k 7 1nF 2.2F 16V 10 1W 17 220F 25V 10k Stand-by control 22 25V 1000F 25V 7 21 22k 14 1 2.2H 47F SGSF 344 10F 16V 560k 8W 6 4 5 16 12 15 13 BY218-100 3.3nF 75 k TEA2260/61 2 4 11 10 2 9 8 3 6 5 100k 220 1nF nF 330 100 220 nF BY299 TEA5170 3 7 1.2 nF 2% 1 nF BZX85-3V0 2.7nF 1kV 18 8 1 47nF 0.170 /1W 1N4148 1k 270 105k 1% 150pF Sync. input 6.8k 100pF POUT : 120W f : 16kHz Small signal secondary ground Power primary ground Secondary ground (isolated from mains) HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S 29/33 376-40.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S IV - TV APPLICATION 140W - 220 VAC - 32kHz SYNCHRONIZABLE All details concerning the determination of external components are described in section III. IV.1 - Application Characteristics - Discontinuous mode flyback SMPS - Stand-by function using the burst mode of TEA 2260. - Switching frequency in burst mode : 16kHz - Switching frequency in normal mode : 32kHz - Nominal mains voltage : 220 VAC - Mains voltage range : 170 VAC to 270 VAC - Output power range in normal mode 25W < Po 140W - Output power range in stand-by mode 2W < Po 45W - Efficiency at full load > 80% - Efficiency in stand-by mode (Po = 7W) > 50% - Short circuit protection - Long duration overload protection - Complete shut down after 3 restarts with fault detection for TEA2260 - Complete shut down when VC2 reaches 2.6V for TEA2261 Line regulation (I135 : 0.8A; I25 : 1A) Output 135V (+/- 0.13%) (210V < VDC < 370V) Output 25V (+/- 0.17%) IV.2 - Transformer Specification - Reference : OREGA.SMT5. G4576-03 - Electrical Data : Figure 41 3 13 20 19 14 6 17 9 22 376-41.EPS 7 21 Wind ing nP nAUX n2 n3 n4 n5 Pin 3-6 7-9 19-13 19-20 14-17 22-21 Inductance 790H 5.4H 338H 4.8H 3.4H 13H Load regulation (VDC = 310V) Output 135V (+/- 0.18%) (I135 : 0.01A to 0.8A; I25 = 1A) Output 25V (+/- 2%) (I135 : O.8A; I25 = 0.5A to 1A) 30/33 Figure 42 170 VAC 3 4 x 1N4007 13 P1 20 PLR811 47k BY218-600 135V 0.8A 270 VAC 150F 385V 39 1N4148 12V 0.5A 470F 25V 100F 250V IV.3 - Electrical Diagram 22k 3W 120k 2.2k 4.7k 6 19 14 BY218-100 7 17 22 1k 2.2 /0.5W 9 P2 BA157 10 1W 3.3 nF 330F 25V BC547C 25V 1A 1000 F 25V 1.2nF 75 k 1000F 25V 22k 1k 1nF 2.2F 16V 7.5V 1A 10k Stand-by control 7 6 4 15 5 12 21 22k 3 14 1 13 16 BY218-100 TEA2260/61 2 4 6 5 11 10 2 9 8 2.2H 47F SGSF 344 10F 16V 220 16W 82k 330 100 18 330 1nF nF 330 nF BZX85-3V0 BY299 TEA5170 3 7 8 1 1 nF 0.135 /1W 2.7nF 1kV 560 pF 2% 47nF 1N4148 150pF 270 100pF POUT : 140W f : 32kHz 1k Sync. input 100k 1% 6.8k Small signal secondary ground Power primary ground Secondary ground (isolated from mains) HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S 31/33 376-42.EPS HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S V - TV APPLICATION 110W -220 VAC - 40kHz REGULATED WITH OPTOCOUPLER This application works in asynchronous mode. The regulation characteristics are very attractive (output power variation range from 1W to 110W due to automatic burst mode (see II.6). In this configuration higher is the regulation loop gain, lower is the output voltage ripple in burst mode (e.g. ouput voltage ripple 0.8% with a loop gain of 15). V.1 - Frequency Soft Start The nominal switching frequency is 40kHz but during the start-up phase the switching frequency is shifted to 10kHz in order to avoid the magnetization of the transformer. Otherwise the second current limitation will be reached at high input voltage and hence the power supply will not start. V.2 - Application Characteristics - Discontinous mode Flyback SMPS - Switching frequency : 40kHz - Nominal mains voltage : 220 VAC - Mains voltage range : 170 VAC to 220 VAC - Output power in normal mode : 30W < Po < 110W - O u t p u t p o we r in b u rs t mod e : 1W < Po < 30W.The transient phase between normal mode and burst mode is determinated automatically as a function of the output power. Hence the regulation of the output voltage is effective for an output power variation of 1W < Po < 110W - Efficiency as full load > 80% - Efficiency in burst mode (Po = 8W) > 50% - Short circuit protection - Open load protection - Long duration overload protection - Complete shutdown after 3 restarts with fault detection for TEA2260 - Complete shut down when VC2 reaches 2.6V for TEA2261 Load regulation (VDC = 310V) Output 135V (+/- 0.15%) (I135 : 0.05A to 0.6A; I25 = 1A) Output 25V (+/- 2.5%) (I135 = 0.6A; I25 : 0.25 to 1A) Line regulation (I135 : 0.6A; I25 : 1A) Output 135V (+/- 0.30%) (210V < VDC <, 370V) Output 25V (+/- 0.30%) Influence of the audio output on the video output Output 135V (+/- 0.1%) (I135 = 0.6A; I25 : 0 1A) Output 135V (+/- 0.05%)(I135 = 0.3A; I25 : 0 1A V.3 - Transformer Specification - Reference : OREGA.SMT5. G4576-02 - Mechanical Data : - Ferrite : B50 - 2 cores : 53 x 18 x 18(mm) THOMSON LCC - Electrical Data : Figure 43 3 13 20 19 14 6 17 9 22 7 21 376-43.EPS Wind ing nP nAUX n2 n3 n4 n5 Pin 3-6 7-9 19-13 19-20 14-17 22-21 Inductance 790H 5.4H 338H 4.8H 3.4H 13H 32/33 Figure 44 170 VAC 4 x 1N4007 3 120k 20 100F 250V 22k 2W 13 PLR811 4.7k 4.7k 7.5V 1A BY218-600 V.4 - Electrical Diagram 270 VAC 120F 385V 135V 0.7A 4 6 2.2 /0.5W 9 BA157 BY218-100 14 5 19 2.2k 470F 25V 39 nF 2.2k 560 10 2W 330F 25V 7 22 17 470F 25V 1 CNX62 25V 1A 2 12V 0.5A 7 6 4 5 12 13 16 15 BY218-100 21 470F 40V BC547A TEA2260/61 8 3 14 1 2.2 k 10nF 11 10 2.2H BY299 2 9 2.2M 56k 220k 47F 220 16W SGSF 344 BZX55C6V2 680 1F pF 1F 330 BC547 100 2.7nF 1kV 1 nF 18 BZX85-3V0 0.120 /1W 27 nF Small signal secondaryground Power primary ground Secondary ground (isolated from mains) POUT : 110W f : 40kHz HIGH PERFORMANCE DRIVER CIRCUITS FOR S.M.P.S 33/33 376-44.EPS Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No licence is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned in this publication are subject to change without noti ce. This publication supersedes and replaces all information previously supplied. SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of SGS-THOMSON Microelectronics. (c) 1994 SGS-THOMSON Microelectronics - All Rights Reserved Purchase of I2C Components of SGS-THOMSON Microelectronics, conveys a license under the Philips I2C Patent. Rights to use these components in a I2C system, is granted provided that the system confo rms to the I2C Standard Specifications as defined by Philips. SGS-THOMSON Microelectronics GROUP OF COMPANIES Australia - Brazil - China - France - Germany - Hong Kong - Italy - Japan - Korea - Malaysia - Malta - Morocco The Netherlands - Singapore - Spain - Sweden - Switzerland - Taiwan - Thailand - United Kingdom - U.S.A. |
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