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P82CF201 Low power, low price dual fan manager
Product data Supersedes data of 2002 Nov 04 2002 Nov 18
Philips Semiconductors
Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
GENERAL DESCRIPTION
The P82CF201 is a 20-pin single-chip dual digital fan controller designed for use with brushless DC fan motors. A thermistor (or temperature resistive sensor) connected to the RthermC input provides the required resistance of 10K to 1.75 K for 30% to 98% PWM duty cycle. With temperature less than 25 C (thermistor resistance more than 10 K) and THRESHOLD is set to LOW, the fan will be off. When temperature rises above 25 C (NTC thermistor at 10K or less), the PWM turns the fan on. The P82CF201 features a Turn-on Delay for a second fan when both fans have to turn-on. This reduces the in-rush current and suppresses acoustic noise. The P82CF201 also features fan fault sensing for enhancing system protection and reliability. It detects the presence of a fan, when the running fan fails or jams using the voltage on VSENSE pin and asserts the fault signal. The fault condition also triggers the maximum PWM applied to the running fan. The fault is also asserted when the thermistor resistance is less than 1.5 K (temperature is over 76 C).
* Constant temperature monitoring ensure reliable motor start-up at
turn-on, coming out of fault condition, or following a transient fault
* Constant fan sensing protect against fan failure and fault condition * Over temperature and fan fail output pin * 20 mA direct drive to LED indicators for fan power supply failure,
fan failure, overheat warning, no fan connect
* 500 mS turn-on delay for the second fan when both fans have to
turn-on, reducing high surge current and noise
* On-chip power-on reset allows operation with no external
components
* The watchdog timer performs self-check and reset function * On-chip oscillator allows operations with no external oscillator
components
* Supports low cost NTC thermistors (for PTC use P82CF202) * Hysteresis control (when THRESHOLD pin is connected to
FEATURES
Vss/Ground) for resistance between 10K (25 C) and 15K (20 C) during cooling to avoid unnecessary fan turning during cool down to VDD) for resistance above 10K during fan failure
* Temperature proportional fan speed control resulting in low
acoustic and longer fan life
* Constant cooling (when THRESHOLD pin is not connected or tied * Maximum PWM is asserted when one fan fails, cooling the system * 20-pin TSSOP package.
* 3.0 V to 5.5 V operating range * Dual PWM fan drive
ORDERING INFORMATION
Type number P82CF201BDH Package Name TSSOP20 Description
Thermistor Range NTC - 1.7 to 32 K
Version SOT360-1
plastic thin shrink small outline package; 20 leads; body width 4.4 mm
PIN CONFIGURATION, 20-PIN TSSOP PACKAGES
FAN1DRIVE VSENSE1 FAN2DRIVE NC VSS VSENSE2 FAULT NC NC
1 2 3 4 5 6 7 8 9
20 NC 19 THRESHOLD 18 RthermC 17 RrefC
P82CF201
16 NC 15 VDD 14 NC 13 NC 12 R thermC DRIVE 11 RrefC DRIVE
NC 10
SU01716
2002 Nov 18
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853-2393 29207
Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
VSENSE2 RrefC DRIVE RthermC DRIVE RC CONTROL FAULT DETECTION VSENSE1 FAULT
RrefC RthermC
RESISTANCE MEASUREMENT
WATCHDOG RESET
PWM 1 & 2
FAN1DRIVE FAN2DRIVE
su01717
Figure 1. Functional Block Diagram.
FUNCTIONAL DESCRIPTION PWM Description
The PWM controls the fan speed by comparing the thermistor resistance to a reference resistance. This ratio translates into the duty cycle of the PWM. The PWM controls the fan speed proportionally to the thermistor resistance. The 30Hz PWM duty cycle has resistance control range from 10K to 1.75 K (typical for NTC thermistor) for 30% to 98% output duty cycle. The PWM pins drive a low cost PNP transistor to give a good drive into the N-channel MOSFET as the low side power switch element in the system. Example of drive circuits will be shown Figure 4. This output has asymmetric complementary drive. Since the system relies on PWM rather than linear power control, the dissipation in the power switch is kept to a minimum. Generally, very small devices (TO-92 or SOT package) will suffice.
Thermistor Measurement Description
A resistor can be measured using a comparator, which compares the RC time of a known reference resistance with the RC time of an unknown resistor value. Since the same capacitor and internal voltage reference are used throughout, it results in a simple calculation.
Runknown = ((RunknownChargingTime*Rreference)/RreferenceChargingTime)
The RC circuits are charged in sequence, until they reach an internal voltage reference of 1.23 V. The RC charging time is measured in the 256uSec - 65535uSec. This range is divided up in 256 time increments. Values of R and C have to be chosen so that it will be within that window. The RC charging time of the reference resistor and thermistor are measured. The thermistor value is calculated by comparing the RC time of the Reference resistor and RC time of the thermistor. Rthermistor = ((RthermistorCTime*Rreference)/RreferenceCTime)
500 mS Delay Turn-On Description
When temperatures rise above 25 C and THRESHOLD is tied to GND (NTC thermistor at 10K or less) for both fans, there is a turn-on delay of 500 mS for the second fan. This reduces the inrush current and suppresses acoustic noise.
2002 Nov 18
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Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
RrefC DRIVE
Rtherm
Rref
RrefC COMPARATOR RthermC
INTERNAL Vref RthermC DRIVE
su01718
Figure 2.
Fan Drive
Depending on the value of the thermistor, the fans will be driven by MOSFET with a PWM signal. When the thermistor resistance is higher than 10 K and THRESHOLD is set to "0" , the fan will be turned off. However when the thermistor resistance is higher than 10 K and THRESHOLD is set to "0" , the fan will be driven by a 30% duty cycle. When the thermistor resistance is 10 K, the fan will be driven by a 30% duty cycle PWM signal. When the thermistor resistance is 1.7 K, the fan will be driven by a 95% duty cycle PWM signal.
Any value in between is linear. A Hysteresis with 30% PWM duty cycle (when THRESHOLD = 0) is introduced to maintain constant cooling when the thermistor cools from 10K (approx. 25 C) to down 15K (approx. 20 C). This reduces on/off cycling for small temperature fluctuation. When THRESHOLD is not connected or tied to "1", the fans will have a 30% PWM duty cycle to maintain constant cooling whenever power is applied. In most application, the VGS (Gate-Source Turn-on voltage) of the MOSFET is lower than the VOH (VDD-0.7) of the fan drive pins. When the VGS of MOSFET is higher than VOH, a non-inverting amplifier (for N-type MOSFet) is needed. For easy reference, this circuit is shown in Figure 5.
Rtherm
1.7K
10K
15K
HYSTERESIS (THRESHOLD = 0)
PWM 30% 95% 98%
su01719
Figure 3.
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Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
Motor Failure Detection and fault Reporting (including watchdog reset)
As shown in Figure 4, the VSENSE input is connected to the collector of NPN transistor through an inverting buffer transistor (2N3904 or PMBT3904D) which amplifies the signal from the low-value current sensing resistor in the ground return leg of the fan circuit. During normal fan operation, communication occurs as each pole of the fan is energized. The fan current develops across the sense resistor(RSENSE). This a voltage follower of the PWM pin. In a running motor, a current will flow through the resistor RSENSE resulting in a voltage drop. The commutation will cause a narrow window where there is no current flow. Motor detection is done by the presence of commutation pulses. If there is constant voltage level on the VSENSE pin when the motor is driven by a PWM signal, the motor is jammed. When there is no voltage at all, the motor might not be connected or the MOSFET is defective. The fault condition also triggers the maximum PWM applied to the running fan. To detect the commutation pulses correctly, the VSENSE input needs a logic high level of 0.2*VDD+0.9 V. (For example:
1.56 V@VDD=3.3 V). The design of proper sense circuitry is a matter of scaling the RSENSE and the gain in buffer transistor to meet the logic high as shown in Figure 4. Assuming the VBE(min) of the transistor is approx. 0.5 V. Table 1 lists some recommended RSENSE values according to the nominal operating current.
Table 1. Recommended values of RSENSE per Figure 4
Nominal Fan Current(mA) 100 200 450 800 Min RSENSE(ohms) 5.1 2.5 2.2 1.0
In addition, when the thermistor resistance falls below 1.7 K (for NTC thermistor) indicating temperature above 76 C, the fault line will be asserted. When the fan fails continuously, the fault signal will be held on LOW.
+12 V
+12 V 3.3 V 12 V FAN
FANXDRIVE
Q1 SI4410DY
3.3 V
VSENSEx
RSENSE (2.2 TYPICAL)
su01720
Figure 4. Interfacing the 82CF201 to a 2-Wire fan.
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Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
12 V FAN1 2-WIRE FAN D1 DIODE
FAN 3.3 V
12 V MOSFET1 VSENSE1 2.4 K TYPICAL FAN1 DRIVE 2.2 RSENSE1 VSENSE1 12 V 4 FAN 3.3 V FAN2 2-WIRE FAN D2 DIODE VSENSE2 12 V FAN FAULT 7 MOSFET2 VSENSE2 2.4 K TYPICAL 8 9 2.2 RSENSE2 10 13 12 11 14 3.3 V 5 6 17 16 15 1 2 20 19 18 C 4.7 F 3.3 V
Rtherm
FAN2 DRIVE 3
P82CF201
Rref 10 K
SU01722
Figure 5. Typical application diagram.
Vref_Peak
0.5 sec
su01721
Figure 6. Waveform at Capacitor wrt Ground.
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Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
ABSOLUTE MAXIMUM RATINGS
PARAMETER Operating temperature under bias Storage temperature range Voltage on any other pin to VSS Maximum IOL per I/O pin Power dissipation (based on package heat transfer, not device power consumption) RATING -55 to +125 -65 to +150 -0.5 to 5.5 V 20 1.5 UNIT C C V mA W
NOTES: 1. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any conditions other than those described in the AC and DC Electrical Characteristics section of this specification are not implied. 2. This product includes circuitry specifically designed for the protection of its internal devices from the damaging effects of excessive static charge. Nonetheless, it is suggested that conventional precautions be taken to avoid applying greater than the rated maximum. 3. Parameters are valid over operating temperature range unless otherwise specified. All voltages are with respect to VSS unless otherwise noted. 4. Parameters are valid over operating temperature range unless otherwise specified. All voltages are with respect to VSS unless otherwise noted.
DC ELECTRICAL CHARACTERISTICS
VDD = 3.0 V to 5.5 V unless otherwise specified; Tamb = 0 C to +70 C, unless otherwise specified SYMBOL PARAMETER Power supply current operating current Input LOW voltage (TTL input) all Rsense Input HIGH voltage (TTL input) all Rsense Output LOW voltage all fan drive pins Output LOW voltage all fan drive pins Output HIGH voltage all fan drive pins IOL=3.2 mA, VDD=3.0 V IOL=20 mA, VDD=3.0 V IOH=-20 A, VDD=3.0 V IOH=-30 A, VDD=4.5 V VOH1 CIO IIL ILI IBOLOW Output HIGH voltage all fan drive pins Input/Output pin capacitance Logical 0 input current, all Rsense Input leakage current, all Rsense, RthermC, RThermDrive, RrefC and RrefCDrive Brownout trip voltage with BOV=1 VIN = 0.4 V VIN = VIL or VIH IOH1=-1.0 mA, VDD=3.0 V TEST CONDITIONS MIN IDD VIL PWM =off, no fault 3.0 V < VDD < 5.5 V 4.0 V < VDD < 5.5 V 3.0 V < VDD < 4.0 V VIH VOL VOL1 VOH 2.2 -0.5 -0.5 0.2 VDD+0.9
- -
LIMITS TYP MAX 5.5 0.2 VDD-0.1 0.7 VDD+0.5 0.4 1.0
- - -
UNIT
mA V V V V V V V V pF A A V
VDD-0.7 V VDD-0.7 V VDD-0.7 V
- - -
15 -50 2 2.69
2.35
COMPARATOR (RTHERMC AND RREFC) ELECTRICAL CHARACTERISTICS
VDD = 3.0 V to 5.5 V unless otherwise specified; Tamb = 0 C to +70 C, unless otherwise specified. SYMBOL VIO VCR IIL PARAMETER Offset voltage comparator inputs1 Common mode range comparator inputs Input leakage current, comparator 0 < VIN < VDD TEST CONDITIONS MIN
-
LIMITS TYP MAX 10 VDD-0.3 10
UNIT mV V A
0
-
NOTE: 1. This parameter is guaranteed by characterization but not tested in production.
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Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
AC ELECTRICAL CHARACTERISTICS
Tamb = 0 C to +70 C, VDD = 3.0 V to 5.5 V unless otherwise specified; VSS = 0 V1 SYMBOL VRef_Peak PWM_DC FIGURE 6 6 PARAMETER MIN Charge_Peak at RefC and RthermC PWM Duty Cycle at fan drive Pin 1.1 30 LIMITS MAX 1.55 98.4 V % UNIT
NOTE: 1. Parameters are valid over operating temperature range unless otherwise specified.
2002 Nov 18
8
Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
TSSOP20: plastic thin shrink small outline package; 20 leads; body width 4.4 mm
SOT360-1
2002 Nov 18
9
Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
REVISION HISTORY
Rev _2 Date 20021118 Description Product data (9397 750 10751); supersedes P82CF201_1 of 2002 Nov 04 (9397 750 10645) Engineering Change Notice 853-2393 29207 (date: 20021115) Modifications:
* Corrected FET type number in Figure 4
_1 20021104 Product data (9397 750 10645); initial version. Engineering Change Notice 853-2393 29144 (date: 20021104).
2002 Nov 18
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Philips Semiconductors
Product data
Low power, low price dual fan manager
P82CF201
Data sheet status
Level
I
Data sheet status [1]
Objective data
Product status [2] [3]
Development
Definitions
This data sheet contains data from the objective specification for product development. Philips Semiconductors reserves the right to change the specification in any manner without notice. This data sheet contains data from the preliminary specification. Supplementary data will be published at a later date. Philips Semiconductors reserves the right to change the specification without notice, in order to improve the design and supply the best possible product. This data sheet contains data from the product specification. Philips Semiconductors reserves the right to make changes at any time in order to improve the design, manufacturing and supply. Relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN).
II
Preliminary data
Qualification
III
Product data
Production
[1] Please consult the most recently issued data sheet before initiating or completing a design. [2] The product status of the device(s) described in this data sheet may have changed since this data sheet was published. The latest information is available on the Internet at URL http://www.semiconductors.philips.com. [3] For data sheets describing multiple type numbers, the highest-level product status determines the data sheet status.
Definitions
Short-form specification -- The data in a short-form specification is extracted from a full data sheet with the same type number and title. For detailed information see the relevant data sheet or data handbook. Limiting values definition -- Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 60134). Stress above one or more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation of the device at these or at any other conditions above those given in the Characteristics sections of the specification is not implied. Exposure to limiting values for extended periods may affect device reliability. Application information -- Applications that are described herein for any of these products are for illustrative purposes only. Philips Semiconductors make no representation or warranty that such applications will be suitable for the specified use without further testing or modification.
Disclaimers
Life support -- These products are not designed for use in life support appliances, devices, or systems where malfunction of these products can reasonably be expected to result in personal injury. Philips Semiconductors customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify Philips Semiconductors for any damages resulting from such application. Right to make changes -- Philips Semiconductors reserves the right to make changes in the products--including circuits, standard cells, and/or software--described or contained herein in order to improve design and/or performance. When the product is in full production (status `Production'), relevant changes will be communicated via a Customer Product/Process Change Notification (CPCN). Philips Semiconductors assumes no responsibility or liability for the use of any of these products, conveys no license or title under any patent, copyright, or mask work right to these products, and makes no representations or warranties that these products are free from patent, copyright, or mask work right infringement, unless otherwise specified.
Contact information
For additional information please visit http://www.semiconductors.philips.com. Fax: +31 40 27 24825
(c) Koninklijke Philips Electronics N.V. 2002 All rights reserved. Printed in U.S.A. Date of release: 11-02
For sales offices addresses send e-mail to: sales.addresses@www.semiconductors.philips.com.
Document order number:
9397 750 10751
Philips Semiconductors
2002 Nov 18 11

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