Ordering number : EN8793B LB11961 Monolithic Digital IC Single-Phase Full-Wave Fan Motor Driver http://onsemi.com Overview The LB11961 is a single-phase bipolar drive motor driver that easily implements direct PWM motor drive systems with excellent efficiency. The LB11961 is optimal for fan motor drive in personal computer power supply systems and CPU cooling fan systems. Features • Single-phase full-wave drive (16V, 1.0A transistors are built in) • Built-in variable speed function controlled by a thermistor input The LB11961 can implement quiet, low-vibration variable speed control using externally clocked high side transistor direct PWM drive. • Built-in regenerative diode (Di); only requires a minimal number of external components. • Built-in HB • Minimum speed setting pin (allows full-speed mode operation at startup) • Operates in full-speed mode when the thermistor is removed. • Built-in lock protection and automatic recovery circuits • FG (speed detection) and RD (lock detection) outputs • Built-in thermal shutdown circuit Semiconductor Components Industries, LLC, 2013 May, 2013 92111 SY 20110915-S00002/31407 TI PC 20070206-S00002 B8-6878 No.8793-1/7 LB11961 Specifications Absolute Maximum Ratings at Ta = 25°C Parameter Symbol VCC maximum output voltage VCC max OUT pin maximum output IOUT max Conditions Ratings current OUT pin output voltage Unit 18 V 1.0 A VOUT max 18 V HB maximum output current IHB max 10 mA VTH input pin voltage VTH max 6 V RD/FG output pin output voltage VRD/FG max 18 V RD/FG output current IRD/FG max 10 mA Allowable power dissipation Pd max When mounted on a circuit board *1 1.1 W Operating temperature Topr -30 to +90 °C Storage temperature Tstg -55 to +150 °C *1 Specified circuit board : 114.3 × 76.1 × 1.6mm3, glass epoxy. Caution 1) Absolute maximum ratings represent the value which cannot be exceeded for any length of time. Caution 2) Even when the device is used within the range of absolute maximum ratings, as a result of continuous usage under high temperature, high current, high voltage, or drastic temperature change, the reliability of the IC may be degraded. Please contact us for the further details. Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability. Recommended Operating Conditions at Ta = 25°C Parameter VCC supply voltage Symbol Conditions Ratings VCC Unit 4.5 to 16 V VTH input level voltage range VTH 0 to 9 V Hall sensor input common-mode VICM 0.2 to 3 V input voltage range Electrical Characteristics Unless otherwise specified Ta = 25°C, VCC = 12V Parameter Symbol Ratings Conditions min Circuit current 6VREG voltage HB voltage ICC1 Drive mode ICC2 Lock protection mode V6VREG VHB I6VREG = 5mA IHB = 5mA typ Unit max 12 18 24 mA 8 11 16 mA 5.8 6 6.2 V 1.10 1.25 1.40 V CPWM high-level voltage VCRH 3.45 3.6 3.75 V CPWM low-level voltage VCRL 1.95 2.05 2.15 V CPWM oscillator frequency FPWM 18 25 32 CT pin high-level voltage VCTH 3.45 3.6 3.75 CT pin low-level voltage VCTL 1.55 1.7 1.85 V ICT charge current ICT1 1.5 2 2.5 μA ICT discharge current ICT2 0.15 0.2 0.25 μA ICT charge/discharge current RCT 8.5 10 11.5 C = 100pF kHz V ratio OUT output low saturation VOL IO = 200mA 0.2 0.3 V VOH IO = 200mA 0.9 1.1 V Zero peak value (including offset and 10 20 mV 0.2 0.3 V 30 μA voltage OUT output high saturation voltage Hall sensor input sensitivity VHN hysteresis) RD/FG output pin low-level VRDL/FGL IRD/FG = 5mA IRDL/FGL VRD/FG = 7V voltage RD/FG output pin leakage current No.8793-2/7 LB11961 Package Dimensions unit : mm (typ) 3313 6.5 Pd max – Ta 1.2 0.5 6.4 Allowable power dissipation, Pd max – W 8 4.4 14 1 1.3 7 0.22 0.15 0.65 0.1 (1.3) 1.5max (2.35) 1.5 Specified circuit board : 114.3×76.1×1.6mm3 glass epoxy board 1.1 1.0 0.8 0.6 0.53 0.4 0.2 0 – 30 – 10 10 30 50 70 90 110 Ambient temperature, Ta – °C SANYO : HSSOP14(225mil) Truth Table VTH IN- IN+ Low High Low (open) Low High High Low High Low High - High Low - Low High CPWM CT High Low Low - High OUT1 OUT2 FG High Low Low Low High Off Off Low Low Low Off Off High Off Low Off High Off RD Mode During rotation − drive (PWM off) On During rotation − regeneration (PWM on) Off Lock protection CPWM – High is the state where CPWM > VTH, and CPWM– Low is the state where CPWM < VTH. Open : The LB11961 operates in full-speed mode when the thermistor is removed. No.8793-3/7 LB11961 Pin Assignment F-GND (P-GND) F-GND (P-GND) OUT2 1 14 OUT1 VCC 2 13 S-GND RMI 3 12 CT VTH 4 11 6VREG CPWM 5 10 IN- FG 6 9 HB RD 7 8 IN+ LB11961 Top view F-GND (P-GND) : The motor system ground and the heat sink. Since the heat generated Since the heat generated by the chip is dissipated through F-GND, the thermal resistance is lowered by increasing the area of the copper foil and solder surface in the printed circuit pattern. S-GND : Control system ground Block Diagram FG RD Thermal protection circuit VCC Constant voltage 6VREG Delay circuit Control circuit 1.3V HB Hall OUT2 M IN+ Delay circuit OUT1 IN− Amplifier with hysteresis Charge/discharge circuit S-GND CT VTH Oscillator circuit CPWM P-GND No.8793-4/7 LB11961 Application Circuit Example *2 CM VCC HB *7 IN− H FG *3 IN+ 6VREG RD *6 *5 RMI *8 OUT1 VTH OUT2 CPWM CP = 100pF *4 CT F-GND *1 CT = 0.47μF to 1μF S-GND F-GND *1. Power supply and ground lines P-GND is connected to the motor power supply system and S-GND is connected to the control circuit power supply system. These two systems should be formed from separate lines and the control system external components should be connected to S-GND. *2. Regeneration power supply stabilization capacitor The capacitor CM provides power supply stabilization for both PWM drive and kickback absorption. A capacitor with a value of over 0.1µF is used for CM. A large capacitor must be used when the coil inductance is large or when the coil resistance is low. Since this IC adopts a technique in which switching is performed by the high side transistor and regeneration is handled by the low side transistor, the pattern connecting CM to VM and P-GND must be as wide and as short as possible. *3. Hall sensor input Lines that are as short as possible must be used to prevent noise from entering the system. The Hall sensor input circuit consists of a comparator with hysteresis (20mV). We recommend that the Hall sensor input level be at least three times this hysteresis, i.e. at least 60mVp-p. *4. PWM oscillator frequency setting capacitor If a value of 100pF is used for CP, the oscillator frequency will be f = 25kHz, and this will be the basic frequency of the PWM signal. *5. RD output This is an open collector output. It outputs a low level when the motor is turning and a high level when it is stopped. This pin must be left open if unused. *6. FG output This is an open collector output, and a rotation count detection function can be implemented using this FG output, which corresponds to the phase switching. This pin must be left open if unused. *7. HB pin This pin provides a Hall effect sensor bias constant-voltage output of 1.25V. *8. RMI pin Connect this pin to VTH if unused. Even if unused, the IC is set internally to operate at a 10% drive duty at the voltage corresponding to the lowest speed. (The capacitor is used to set up full-speed mode at startup.) No.8793-5/7 LB11961 Control Timing Chart (VCC × 28%) Thermistor removed Internal lowest speed setting voltage f = 25kHz (CP=100pF) High on duty 3.6V (VCC × 30%) RMI voltage CPWM 2.0V (VCC × 16%) Low on duty 0V Set minimum speed Full speed mode PWM control variable speed mode Low temperature High temperature 12V VCC 0V FG 1. Set minimum speed mode A VTH voltage level is generated when the thermistor detects the set temperature. At low temperatures, the fan motor turns at the lowest speed, which is set with the RMI pin. The LB11961 compares the CPWM oscillator voltage with the RMI pin voltage and sets the duty for the lowest drive state. 2. High speed ↔ low speed mode The PWM signal is controlled by comparing the CPWM oscillation voltage that cycles between 1.2V and 3. 8V and the VTH voltage. When the VTH voltage is lower, the high and low side transistors are turned on, and when the VTH voltage is higher, the high side transistor is turned off and the coil current is regenerated through the low side transistor. Thus the output on duty increases as the VTH voltage becomes lower, the coil current increases, and the motor speed increases. Rotation speed feedback is provided by the FG output. 3. Full-speed mode The LB11961 switches to full-speed mode above a certain temperature. 4. Thermistor removed mode If the thermistor is removed, the VTH input voltage will rise. However, the output will go to full drive at 100% and the motor will run at full speed. No.8793-6/7 LB11961 ON Semiconductor and the ON logo are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC owns the rights to a number of patents, trademarks, copyrights, trade secrets, and other intellectual property. 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