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NJU6052
PRELIMINARY
White LED Driver with Automatic Dimming Control
! GENERAL DESCRIPTION The NJU6052 is a white LED driver with an automatic dimming control. It contains an output driver, a PWM controller, a luminance sensor control (power supply for sensor & A/D converter), a step-up DC/DC converter, a serial interface, etc. The output driver ensures a 60mA maximum capability which allows the connection of 12 white LEDs (4 series x 3 parallels). Depending on the ambient light sensed with an external luminance sensor, the PWM controller controls PWM duty in 8 steps preselected out of 64 steps. In addition, the frequency of the DC/DC converter is high so that it permits the use of small, low-profile inductors and capacitors to minimize the footprint in space-conscious applications. All of these benefits make the NJU6052 suitable for the battery-powered portable applications such as a cellular phone, a camcorder, PDA, etc. ! PACKAGE OUTLINE
NJU6052KN1
NJU6052V
! FEATURES
# Drives up to 12 white LEDs (4 series x 3 parallels)
VSW = 18.0V(Max.), IOUT = 60mA
# Built-in PWM Dimming Control
(Selectable 8 out of 64 steps)
# Built-in Luminance Sensor Control (Power Supply for Sensor & A/D converter) # # # # # #
(No MPU-access required after initial setting) Built-in Temperature Compensation Circuit to Suppress the Characteristic Degradation of LEDs Uses Small Inductor and Capacitors 1.8V to 3.6V Operating Voltage for Logic Circuits (VDDL) 3.0V to 5.5V Operating Voltage for Step-up Circuits (VDD) CMOS Technology Package : QFN28 / SSOP20
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NJU6052
! QFN20 PIN CONNECTIONS (TOP VIEW)
VSS
VSS
VSS
REF
NC
NC
CX
NC FB VOUT SW SW SW NC
NC VSO SENS RSTb SCK DATA NC
! SSOP20 PIN CONNECTIONS (TOP VIEW)
NC
TEST
NC
VDD
VDDL
REQ
NC VOUT FB VSS VSS VSS REF CX VSO SENS RSTb
SW SW SW TEST NC VDD VDDL REQ DATA SCK
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NJU6052
! PIN DESCRIPTION
QFN 4 5 25 26 27 10 9 2 6 12 11 24 23 18 19 20 16 13 17 1 3 7 8 14 15 21 22 28 No. SSOP 6 7 1 2 3 10 9 4 8 12 11 20 19 16 17 18 14 13 15 SYMBOL VDD VDDL TYPE Power Power DESCRIPTIONS VDD Power Supply - Power supply for step-up voltage VDDL Power Supply - Power supply for logic voltage. - Relation:1.8V VDDL VDD should be maintained. Switch - All these terminals should be connected together. Shift Clock - Serial data is latched on the rising edge of SCK. Serial Data Test - This terminal must be open. Data Request "L" : Writing command data "H" : Reading sensor data Luminance Sensor Connection Reset - Active "L". Input - This terminal is connected to LED anode. Feedback Ground - All these terminals should be connected together. Oscillator Capacitor Connection / External Clock Input VSO Power Supply - Power supply for luminance sensor - 2.4V typical Reference Voltage - This terminal must be open.
SW SCK DATA TEST REQ SENS RSTb VOUT FB VSS CX/TCLK VSO REF
Input Input Input / Output Output Input Input Input Input Input Power Input Output Input
5
NC
-
Non Connection - These terminals must be open.
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NJU6052
! BLOCK DIAGRAM
L1 VDD VSO Regulator SW D1 VOUT
C1
SENS A/D
Converter
C2
Register
PWM Controller A1 FB
VDDL REQ SCK DATA
Reset
Serial Interface
Logic REF VREF A2 RLED
RSTb
CX/TCLK
OSC
VSS
TEST
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NJU6052
! FUNCTIONAL DESCRIPTONS (1) LED CURRENT CONTROL The NJU6052 incorporates the LED current control circuit to regulate the LED current (ILED), which is programmed by the feedback resistor (RLED) connected between the FB and VSS terminals. The reference voltage VREF is internally regulated to 0.6V typical and connected to the positive input of the built-in comparator A1. Formula (1) is used to choose the value of the RLED, as shown below.
RLED =
VREF I LED
--- Formula (1)
VREF=0.6V (TYP.) Referring to the block diagram is recommended for understanding the operation of the LED current control. The ILED is the constant current programmed by the RLED. When the feedback voltage on the FB terminal reaches above the reference voltage VREF on the REF terminal (i.e., ILED is above the level programmed by RLED), the output capacitor C2 delivers the ILED. Once the feedback voltage drops below the reference voltage (i.e., ILED drops below the level programmed by RLED), the comparator A1 detects it and turns on the internal MOS switch, then the current of the inductor L1 begins increasing. When this switch current reaches 720mA and the comparator A2 detects it, or when the predetermined switch-on-period expires, the MOS switch is turned off. The L1 then delivers current to the output through the diode D1 as the inductor current drops. After that, the MOS switch is turned on again and the switch current increases up to 720mA. This switching cycle continues until the ILED reaches the level programmed by the RLED, then the ILED is maintained constant. When the feedback voltage is less than 1/2*VREF, the current limit of the MOS switch is reduced to 500mA typical. This action reduces the average inductor-current, minimizes the power dissipation and protects the IC against high current at start-up. The total forward-voltage of the LEDs must be greater than the power supply voltage VDD, otherwise the LEDs remain lighting up, being out of control.
(2) OSCILLATOR The built-in oscillator incorporates a reference power supply, so its frequency is independent from the VDD. The frequency is varied by the external capacitor CX, as shown in Figure 7.
(3) LUMINANCE SENSOR CONTROL The luminance sensor control circuits consist of the power supply for sensor and the A/D converter. The A/D converter senses the voltage on the SENS terminal and selects 1 out of 8 registers (PWM REGISTER 0-7). And the data in the selected register is reflected to the PWM duty (PWM dimming control). The contents of the registers can be programmed through the serial interface, in other words, the dimming control is user-settable. The voltage sense and the register selection are updated at regular intervals, and the interval period is set by the "DIVIDE" bits. The selected register is held by setting "1" at the "HOLD" bit of the command data.
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NJU6052
(4) PWM DIMMING CONTROL By setting the duty data at "PWM REGISTER" bits, 8 out of 64 registers are assigned to the PWM REGISTER 0-7. The PWM duty is changed depending on the register selected by the SENS voltage. The relation between the PWM REGISTER and its duty is shown below.
TABLE 1 PWM DUTY vs. PWM REGISTER REGISTER DUTY REGISTER 0,0,0,0,0,0 OFF 0,1,0,0,0,0 0,0,0,0,0,1 3.13% 0,1,0,0,0,1 0,0,0,0,1,0 4.69% 0,1,0,0,1,0 0,0,0,0,1,1 6.25% 0,1,0,0,1,1 0,0,0,1,0,0 7.81% 0,1,0,1,0,0 0,0,0,1,0,1 9.38% 0,1,0,1,0,1 0,0,0,1,1,0 10.94% 0,1,0,1,1,0 0,0,0,1,1,1 12.50% 0,1,0,1,1,1 0,0,1,0,0,0 14.06% 0,1,1,0,0,0 0,0,1,0,0,1 15.63% 0,1,1,0,0,1 0,0,1,0,1,0 17.19% 0,1,1,0,1,0 0,0,1,0,1,1 18.75% 0,1,1,0,1,1 0,0,1,1,0,0 20.31% 0,1,1,1,0,0 0,0,1,1,0,1 21.88% 0,1,1,1,0,1 0,0,1,1,1,0 23.44% 0,1,1,1,1,0 0,0,1,1,1,1 25.00% 0,1,1,1,1,1
DUTY 26.56% 28.13% 29.69% 31.25% 32.81% 34.38% 35.94% 37.50% 39.06% 40.63% 42.19% 43.75% 45.31% 46.88% 48.44% 50.00%
REGISTER 1,0,0,0,0,0 1,0,0,0,0,1 1,0,0,0,1,0 1,0,0,0,1,1 1,0,0,1,0,0 1,0,0,1,0,1 1,0,0,1,1,0 1,0,0,1,1,1 1,0,1,0,0,0 1,0,1,0,0,1 1,0,1,0,1,0 1,0,1,0,1,1 1,0,1,1,0,0 1,0,1,1,0,1 1,0,1,1,1,0 1,0,1,1,1,1
DUTY 51.56% 53.13% 54.69% 56.25% 57.81% 59.38% 60.94% 62.50% 64.06% 65.63% 67.19% 68.75% 70.31% 71.88% 73.44% 75.00%
REGISTER 1,1,0,0,0,0 1,1,0,0,0,1 1,1,0,0,1,0 1,1,0,0,1,1 1,1,0,1,0,0 1,1,0,1,0,1 1,1,0,1,1,0 1,1,0,1,1,1 1,1,1,0,0,0 1,1,1,0,0,1 1,1,1,0,1,0 1,1,1,0,1,1 1,1,1,1,0,0 1,1,1,1,0,1 1,1,1,1,1,0 1,1,1,1,1,1
DUTY 76.56% 78.13% 79.69% 81.25% 82.81% 84.38% 85.94% 87.50% 89.06% 90.63% 92.19% 93.75% 95.31% 96.88% 98.44% 100.00%
The relation between the PWM REGISTER and SENS voltage is reversed by the "REV" bit, as follows.
TABLE 2 REV vs. PWM REGISTER REV PWM REGISTER PWM REGISTER0 PWM REGISTER1 PWM REGISTER2 PWM REGISTER3 PWM REGISTER4 PWM REGISTER5 PWM REGISTER6 PWM REGISTER7 PWM REGISTER7 PWM REGISTER6 PWM REGISTER5 PWM REGISTER4 PWM REGISTER3 PWM REGISTER2 PWM REGISTER1 PWM REGISTER0
0
1
Note 1) For the information on the relation between PWM duty and LED current (ILED), refer to "(9-1) PWM DUTY and LED CURRENT". Note 2) For the information on the relation between SENS voltage and PWM REGISTER, refer to "DC ELECTRICAL CHARACTERISTICS".
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NJU6052
(5) SERIAL INTERFACE (5-1) SERIAL DATA WRITE The serial data is latched into the shift register on the rising edge of the serial clock (SCK), and determined on the rising edge of the data request (REQ). The serial data format should be the MSB first. For COMMAND data transmission, the command data 1 (CMD1) and the command data 2 (CMD2) should be continuous. The CMD1 is first, then the CMD2. If only 1-byte data is transferred, this data is recognized as the CMD1. Do not transmit 3 bytes or more, because 3rd data is used only for maker test and the 4th and later are ignored. If it's absolute necessary to send the 3 bytes or more in the user's application, the only data (0,0,0,0,0,0,0,0) as the 3rd data can be accepted. For DUTY data transmission, 8 bytes for PWM REGISTER 0-7 should be continuous. The order is : PWM REGISTER 0, 1, 2, 3, 4, 5, 6 and 7. If 7bytes or less are transferred, all bytes are accepted. And if 9 bytes or more, the 9th and later are ignored. Note that the data should be in 8*n bits (n=integer number), otherwise it may cause malfunctions. And the SCK should be "0" when the REQ is changed.
SERIAL DATA FORMAT TABLE 3-1 Command Data 1 B7 B6 B5 B4 0 SOFF BRIGHT TABLE 3-2 Command Data 2 B7 B6 B5 B4 0 0 0 0 TABLE 3-3 Duty Data B7 B6 B5 1 *
B3
B2 STBY
B1 HOLD
B0 REV
B3 0
B2 0
B1 B0 DIVIDE
B4
B3 B2 PWM REGISTER
B1
B0
FIGURE 1 REQ
COMMAND DATA TRANSMISSION
SCK DATA B7 6 5 4 3 2 1 0 B7 6 5 4 3 CMD2 2 1 0
CMD1
FIGURE 2 REQ
DUTY DATA TRANSMISSION
SCK DATA B7 6 5 4 0 3 2 1 0 B7 1 6 0 B7 6 0 6 B7 6 7
PWM REGISTER
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NJU6052
(5-2) SENSOR DATA READ The DATA terminal becomes output state by setting the REQ terminal to "1" after the command data transmission. And the sensor data is read out, synchronizing with the SCK. The bit number corresponding to a selected register is "1" and the others are "0", as shown below.
FIGURE 3 SENSOR DATA READ (REV=0, PWM REGISTER4 selected)
REQ SCK DATA B7 Command Data (Input) 0 1 2 3 4 5 6 7
Sensor Data (Output)
(5-3) SOFF and BRIGHT By setting "1" at the SOFF bit, the luminance sensor control is disabled and the PWM duty is controlled by the BRIGHT bits, as shown below.
TABLE 4 SOFF and BRIGHT SOFF BRIGHT
REV
0
-
0
1
000 001 010 011 100 101 110 111
-
PWM REGISTER PWM REGISTER0 PWM REGISTER1 PWM REGISTER2 PWM REGISTER3 PWM REGISTER4 PWM REGISTER5 PWM REGISTER6 PWM REGISTER7 PWM REGISTER0 PWM REGISTER1 PWM REGISTER2 PWM REGISTER3 PWM REGISTER4 PWM REGISTER5 PWM REGISTER6 PWM REGISTER7
Note 1) When SOFF="0", luminance sensor control is enabled and PWM REGISTER is selected according to SENS voltage. Note 2) For the information on the relation between SENS voltage and PWM REGISTER, refer to "DC ELECTRICAL CHARACTERISTICS".
(5-4) STBY By setting "1" at the STBY bit, the NJU6052 goes into the standby mode, as follows. - DC/DC converter, oscillator, reference voltage generator, and power supply for sensor are halted. - The contents of PWM REGISTER are maintained. - Luminance sensor control circuit is initialized.
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NJU6052
(5-5) HOLD By setting "1" at the HOLD bit, the selected PWM REGISTER is held and the luminance sensor control cannot be used. In other words, this setting works so that the luminance of the LEDs doesn't change even if the SENS voltage changes. The selection is initialized to the PWM REGISTER 0 by the reset. And when the standby is released, the selection is initialized to the PWM REGISTER 0 at REV="0" or the PWM REGISTER 7 at REV="1". (5-6) REV By setting "1" at the REV bit, the correspondence between the PWM REGISTER and SENS voltage is reversed.
TABLE 5 REV REV
0
1
PWM REGISTER PWM REGISTER0 PWM REGISTER1 PWM REGISTER2 PWM REGISTER3 PWM REGISTER4 PWM REGISTER5 PWM REGISTER6 PWM REGISTER7 PWM REGISTER7 PWM REGISTER6 PWM REGISTER5 PWM REGISTER4 PWM REGISTER3 PWM REGISTER2 PWM REGISTER1 PWM REGISTER0
(5-7) DIVIDE By setting the DIVIDE bits, the sensor-sampling-time (tSENS) and PWM frequency (fPWM) are changed. Note that these parameters are varied depending on the oscillation frequency (FOSC). The formula (2) gives the sensor-sampling-time.
t sens =
TABLE 6
2 (17 + N ) f OSC
(sec)
--- Formula (2)
SENSOR SAMPLING TIME N 0 1 2 3 FOSC 100kHz 200kHz 0.655 400kHz 0.328 0.655 800kHz 0.164 0.328 0.655
DIVIDE 00 01 10 11
1.311
2.621 5.243 10.486
1.311
2.621 5.243
1.311
2.621
1.311
UNIT : sec
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NJU6052
And, the formula (3) gives the PWM frequency.
f pwm =
TABLE 7
f 1 ( 3osc ) 64 2 + N
( Hz )
--- Formula (3)
PWM FREQUENCY N 0 1 2 3 FOSC 100kHz 200kHz 390.6 400kHz 781.3 390.6 800kHz 1562.5 781.3 390.6
DIVIDE 00 01 10 11 NOTE)
195.3
97.7 48.8 24.4
195.3
97.7 48.8
195.3
97.7
195.3
UNIT : Hz
PWM frequencies written in bold or neighbors are recommended, otherwise it might cause LED flickering.
(6) LEVEL SHIFTER The level shifter allows the communication with the MPU working at the power supply voltage lower than the VDD. Apply the MPU power-supply-voltage on the VDDL terminal. The voltage range is: 1.8V(7) RESET By setting the RSTB pin to "L", the NJU6052 is initialized into the following default status.
TABLE 8 RESET REGISTER REV HOLD STBY BRIGHT SOFF DIVIDE PWM REGISTER0-7
DATA 0 0 0 000 0 00 000000
Default status Refer to Table 5 Sensor sampling is enabled Standby Off Luminance sensor control is enabled PWM duty 0% (LED off)
(8) TEMPERATURE COMPENSATION The reference voltage (VREF) generator has temperature compensation, which suppresses the characteristic degradation of LEDs at high temperatures. Refer to "ILED vs. Temperature" shown in the "DC Electrical Characteristics".
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NJU6052
(9) APPLICATIONS INFORMATION (9-1) PWM DUTY and LED CURRENT The average LED current is programmed with the single resistor RLED and the PWM duty, as shown in Formula (4).
I LED(avg) = I LED(max) I LED(max) = VREF RLED DUTY 100 --- Formula (4)
(9-2) INDUCTOR SELECTION Formula (5) is used to choose an optimum inductor, as shown below:
V 2 OUT - VIN I LED L= 2 I LIMIT f OSC
--- Formula (5)
: Power conversion efficiency (= 0.7 to 0.8)
The power supply voltage VIN may fluctuate in battery-powered applications. For this reason, the minimum voltage should be applied to the VIN in Formula (5). The NJU6052 has about 200ns of delay time (TDELAY), which is defined as the period from the reach of the current limit 720mA to the MOS-switch-off. The TDELAY may cause an overshoot-inductor-current, which is called the peak current IL,PEAK, and calculated by Formula (6). Therefore, it is recommended that an inductor with a rating twice of the IL,PEAK and a low DCR (DC resistance) be used for high efficiency.
VIN (max) - VDS TDELAY I L,PEAK = I LIMIT + L
VDS VIN(MAX)
--- Formula (6)
: Drain-Source voltage of the MOS switch (=ILIMIT*RON) : Maximum of VIN Voltage
(9-3) DIODE SELECTION A Schottky diode with a low forward-voltage-drop and a fast switching-speed is ideal. And the diode must have a rating greater than the output voltage and the output current in the system. (9-4) CAPACITOR SELECTION A low ESR (Equivalent Series Resistance) capacitor should be used at the output to minimize output ripples. A multi-layer ceramic capacitor is the best selection for the NJU6052 application because of not only the low ESR but its small package. A ceramic capacitor as the input decoupling-capacitor is also recommended and should be placed as close to the NJU6052 as possible.
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NJU6052
! ABSOLUTE MAXIMUM RATINGS
PARAMETERS VDD Power Supply VDDL Power Supply Input Voltage Input Voltage Switch Voltage Power Dissipation Operating Temperature Storage Temperature NOTE1) NOTE2) SYMBOL VDD VDDL VIN1 VIN2 VSW PD Topr Tstg CONDITIONS RATINGS -0.3 to +6 -0.3 to VDD -0.3 to VDD+0.3 -0.3 to VDDL+0.3 +18.0 T.B.D. -40 to +85 -55 to +125 UNIT V V V V V mW C C 3 4 5 Ta=25C NOTE
CX/TCLK, REF, FB, SENS terminals REQ, DATA, SCK, RSTb Terminals SW terminal
NOTE3)
All voltages are relative to VSS = 0V reference. Do not exceed the absolute maximum ratings, otherwise the stress may cause a permanent damage to the IC. It is also recommended that the IC be used in the range specified in the DC electrical characteristics, or the electrical stress may cause mulfunctions and affect the reliability. The switch voltage VSW is the highest voltage in the system. This voltage must not exceed the absolute maximum rating. VSW =VF(LED) x N(LED) +VF(D1) +VREF VF(LED) N(LED) VF(D1) :Forward Voltage of LED :The Number of LEDs :Forward Voltage of Diode D1
For instance, when VF(LED) = 3.6V, N(LED)=4pcs, VF(D1)=0.3V, VREF=0.6V(TYP), VSW = 3.6V x 4 + 0.3V + 0.6V = 15.3V. NOTE4) NOTE5) Mounted on the glass epoxy board (50mm x 50mm x 1.6mm) Mounted on the board specified by EIA/JEDEC (2-layer FR-4, 76.2mm x 114.3mm x 1.6mm)
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NJU6052
! DC ELECTRICAL CHARACTERISTICS
VDDL=1.8 to 3.6V, VDD=3.0 to 5.5V, Ta=-40 to 85C RATINGS Unit Note MIN. TYP. MAX. 3.0 1.8 60 Ta=25C DC/DC Converter OFF fosc=350kHz 0.558 0.60 1.0 2.23 SENS terminal, REV=0 SENS terminal, REV=0 SENS terminal, REV=0 SENS terminal, REV=0 SENS terminal, REV=0 SENS terminal, REV=0 SENS terminal, REV=0 SENS terminal, REV=0 SCK, DATA, REQ, RSTb terminals SCK, DATA, REQ, RSTb terminals DATA terminals VDDL=1.8V, IOL=0.4mA DATA terminals VDDL=1.8V, IOH= - 0.04mA VDD=3V, CX=82pF VDD=3V, CX=82pF SW terminal, VDD=4.2V VFB>VREF/2, Ta=25C SW terminal, VDD=4.2V ISW=720mA, Ta=25C VOUT terminal 0 0.015VSO 0.030VSO 0.060VSO 0.110VSO 0.220VSO 0.440VSO 0.880VSO 0 0.8VDDL 2.40 0.642 1.4 1 2.57 0.0055VSO 0.0185VSO 0.040VSO 0.090VSO 0.180VSO 0.360VSO 0.720VSO VSO 0.2VDDL VDDL 0.2VDDL 0.8VDDL 210 77 610 350 82 720 1 17.5 490 87 825 1.4 5.5 3.6 V V mA V mA uA V V V V V V V V V V V V V kHz % mA V V
PARAMETERS VDD Power Supply VDDL Power Supply Output Current Reference Voltage Operating Current Standby Current VSO Power Supply PWM REGISTER0 Selected Voltage PWM REGISTER1 Selected Voltage PWM REGISTER2 Selected Voltage PWM REGISTER3 Selected Voltage PWM REGISTER4 Selected Voltage PWM REGISTER5 Selected Voltage PWM REGISTER6 Selected Voltage PWM REGISTER7 Selected Voltage Input "L" Level Input "H" Level Output "L" Level Output "H" Level Oscillation Frequency Oscillation Duty Switch Current Limit Switch On Voltage Over Voltage Protection
SYMBOL VDD VDDL IOUT VREF IOPR ISTBY VSO VD0 VD1 VD2 VD3 VD4 VD5 VD6 VD7 VIL VIH VOL VOH fOSC DOSC ILIMIT VDS(on) VOVP
CONDITIONS
1 2 3 4 5
6
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NJU6052
NOTE1) Output Current Test Conditions ! TEST Command Command Data 1 Command Data 2 Duty Data B7 0 0 1 B6 1 1 * B5 0 0 1 B4 0 0 1 B3 0 0 1 B2 0 0 1 B1 0 0 1 B0 0 0 1 *: "Don't care"
! TEST Circuit VDD D1 L1 C1 C2 RLED RLOAD R1 fOSC
:5V :Schottky diode :10uH :4.7uF :1uF :30 :750 :100k :350kHz / Duty 82%
L1
D1
A
C1 VOUT SW SW SW NC NC FB
C2
NC TEST NC VDD VDDL REQ
NC VSS VSS VSS REF CX/TCLK NC VSO NC NC DATA SCK RSTb SENS RLED fOSC RLOAD
NC Controller
R1
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NJU6052
NOTE2) TEMPERATURE COMPENSATION The reference voltage (VREF) generator has temperature compensation, which suppresses the characteristic-degradation of LEDs at high temperatures. The VREF is regulated to 0.6V typical in the temperature range up to 45C, and gradually decreases as the ambient temperature rises in the range higher than 45C.
1.0
VREF[V]
0.5
0.0 -50 -25 0 25 50 TEMPERATURE[] 75 100
VREF VS TEMPERATURE
FIGURE 4
VREF vs. TEMPERATURE
30
RLED=30 RLED=40
ILED[mA]
20
10
0 -50 -25 0 25 50 TEMPERATURE[] 75 100
ILED VSTEMPERATURE
FIGURE 5
ILED vs. TEMPERATURE
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NJU6052
NOTE3) Operating Current Test Conditions ! TEST Command Command Data 1 Command Data 2 Duty Data B7 0 0 1 B6 1 1 * B5 0 0 1 B4 0 0 1 B3 0 0 1 B2 0 0 1 B1 0 0 1 B0 0 0 1 *: "Don't care"
NOTE4) Standby Current ! TEST Command Command Data 1 Command Data 2 B7 0 0 B6 * 1 B5 * 0 B4 * 0 B3 * 0 B2 1 0 B1 * 0 B0 * 0 *: "Don't care"
! TEST Circuit (Operating Current, Standby Ciurrent) LED D1 L1 C1 C2 RLED R1 fOSC :VF=3.6V, ILED=20mA :Schottky diode :10uH :4.7uF :1uF :30 :100K :350kHz / Duty 82%
L1
D1
A
C1 VOUT SW SW SW NC NC FB
C2
NC TEST NC VDD VDDL REQ
NC VSS VSS VSS REF CX/TCLK NC RLED NC VSO NC DATA SCK RSTb SENS
Controller
NC R1
fOSC
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NJU6052
NOTE5) VSO Power Supply Test Condition ! TEST Command Command Data 1 Command Data 2 ! TEST Circuit LED D1 L1 C1 C2 RLED R1 R2 fOSC B7 0 0 B6 1 1 B5 1 0 B4 1 0 B3 1 1 B2 0 0 B1 0 0 B0 0 0
:VF=3.6V, ILED=20mA :Schottky diode :10uH :4.7uF :1uF :30 :100K :1K :350kHz / Duty 82%
L1
D1
C2 C1 VOUT SW SW SW NC NC NC VSS VSS VSS REF CX/TCLK NC RLED VSO NC NC DATA SCK RSTb SENS R1 fOSC
NC TEST NC VDD VDDL REQ NC
Controller
FB
v
R2
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NJU6052
NOTE6) OSCILLATOR The built-in oscillator incorporates a reference power supply, so its frequency is independent from the VDD. The frequency is varied by the external capacitor CX, as shown below.
fOSC vs CX
1000 900 800 700 600 500 400 300 200 100 0 0 100 200 CX(pF) 300 400 500
fOSC(kHz)
Figure 7
fOSC vs. CX
(Reference but not guaranteed)
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NJU6052
! AC ELECTRICAL CHARACTERISTICS
PARAMETERS SCK Clock Cycle SCK Clock Width "H" Level "L" Level SYMBOL tSCCY tWSCH tWSCL tREH tDIS tDIH tD0 tRES tWREH tr tf tRSL VDDL=1.8 to 3.6V, VDD=3.0 to 5.5V, Ta=-40 to 85C RATINGS UNIT TYP. MAX. 200 100 100 us ns ns ns ns ns ns ns ns ns ns us
MIN. 1.0 400 400 800 400 400 400 800 1.0
REQ Hold Time Data Set-Up Time Data Hold Time Output Data Delay Time CL=20pF REQ Set-Up Time REQ High Level Width REQ,SCK,DATA Rising Time REQ,SCK,DATA Falling Time RSTB Pulse Width
Serial Input Timing REQ
tWSCL tWSCH tRES tREH tWREH
SCK
tDIS tDIH tSCCY
DATA
B7
B6
B5
Bn
B0
Serial Output Timing REQ
tWSCL tWSCH tRES tREH
SCK
tSCCY
tDO
DATA
B7
B6
B5
Bn
B0
Reset Input Timing
tRSL
RSTb
0.3VDD 0.3VDD
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NJU6052
! TYPICAL PERFORMANCE
1. Oscillation Frequency
@VDD=3V,ILOAD=30mA,Duty=82%
@VDD=3V,ILOAD=60mA,Duty=82% 18 16 14 Output Voltage[V] 12 10 8 6 4 2 0 100 200 300 400 500 600 700 800 L=4.7uH L=6.8uH L=10uH
18 16 14 Output Voltage[V] 12 10 8 6 4 2 0 100 200 300 400 500 600 700 800 Frequency[kHz]
L=4.7uH L=6.8uH L=10uH
Frequency[kHz]
@VDD=5V,ILOAD=30mA,Duty=82%
@VDD=5V,ILOAD=60mA,Duty=82% 18 16 14 Output Voltage[V] 12 10 8 6 4 2 L=4.7uH L=6.8uH L=10uH
18 16 14 Output Voltage[V] 12 10 8 6 4 2 0 100 200 300 400 500 600 700 800 Frequency[kHz]
L=4.7uH L=6.8uH L=10uH
0 100
200
300
400
500
600
700
800
Frequency[kHz]
Figure 8
Output Voltage vs. Frequency
- 20 -
Ver.2004-02-26
NJU6052
2. Load Current
@VDD=3V,L=10uH,Duty=82%
@VDD=5V,L=10uH,Duty=82%
18 16 14 Output Voltage[V] 12 10 8 6 4 2 0 0 10 20 30 40 50 60 70 80 90 100 Load Current[mA]
f=210kHz f=350kHz f=490kHz
18 16 14 Output Voltage[V] 12 10 8 6 4 2 0 0 10 20 30 40 50 60 70 80 90 100 Load Current[mA]
f=210kHz f=350kHz f=490kHz
Figure 9
Output Voltage vs. Load Current
@VDD=3V,L=10uH,Duty=82% 100 90 80 70
@VDD=5V,L=10uH,Duty=82%
100 90 80 70 Efficiency[%] 60 50 40 30 20 10 0
0 10 20 30 40 50 60 70 80 90 100
Efficiency[%]
60 50 40 30 20 10 0 Load Current[mA] f=210kHz f=350kHz f=490kHz
f=210kHz f=350kHz f=490kHz
0
10
20
30
40
50
60
70
80
90 100
Load Current[mA]
Figure 10
Efficiency vs. Load Current
Ver.2004-02-26
- 21 -
NJU6052
3. ! Typical Performance TEST Circuit TEST Command
B7 B6 B5 B4 B3 B2 B1 B0
Command Data 1 Command Data 2 Duty Data
0 0 1
1 1 *
0 0 1
0 0 1
0 0 1
0 0 1
0 0 1
0 0 1 * :"Don't care"
!
TEST Circuit
D1 L1 C1 C2 RLED RLOAD R1
:Schottky diode :10uH :4.7uF :1uF :4.2k :100k :100k
L1
D1
C2 C1 VOUT SW SW SW
NC
NC NC VSS VSS VSS REF CX/TCLK NC RLED RLOAD
NC TEST NC VDD VDDL REQ NC
FB
V
Controller
R1
VSO
NC
NC
DATA
SCK
RSTb
SENS
fOSC
- 22 -
Ver.2004-02-26
NJU6052
! TYPICAL APPLICATION CIRCUIT
L1
D1
C2 C1 VOUT
SW
SW
SW
NC
NC NC VSS VSS VSS REF CX/TCLK NC NC
NC TEST NC VDD VDDL REQ NC
Controller
R1
FB VSO SENS
NC
DATA
SCK
RSTb
C3
RLED
Photo sensor
R2
[CAUTION] The specifications on this databook are only given for information , without any guarantee as regards either mistakes or omissions. The application circuits in this databook are described only to show representative usages of the product and not intended for the guarantee or permission of any right including the industrial rights.
Ver.2004-02-26
- 23 -

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