KA3902 Fairchild Semiconductor, KA3902 Datasheet
KA3902
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KA3902 Summary of contents
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... FAN8902(KA3902) DC FAN Motor Controller Features • Built-in PWM Current Control Circuit • Built-in 5V Regulator • Low Supply Current • Stalled Motor Current Limitation • Built-in Over Voltage Protection (OVP) • Built-in Over Current Protection (OCP) • Built-in Load Dump Protection • Built-in Thermal Shutdown (TSD) Circuit • ...
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... Optional OP Amplifier (-) Input Signal GND Oscillator Time Constant Voltage Reference (5V) Maximum Current Reference Input No Connection Minimum Current Reference Input Motor Current Sense Voltage Input Power GND Drive Output V CC Motor Current Maximum Reference Input FAN8902(KA3902 VCC 12 OUT ...
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... FAN8902(KA3902) Internal Block Diagram 6 Vref CH 7 1.3V CMD CMDa 2 3 CMDb 3 UVLO Vref + + PWM LOGIC PWM Comparator + Oscillator OVP 36V TSD 12 OUT 11 PGND SGND ...
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... Vref Temperature Stability Frequency Stability Operating Temperature Storage Temperature Symbol CMD I OPK P D Symbol Min. V 9.0 CC Symbol Temp V - - OPR T - STG FAN8902(KA3902) Value Unit 0 Typ. Max Unit 12.0 32.0 V Value Unit 200 -40 ~ +90 C -60 ~ +150 C 4 ...
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... FAN8902(KA3902) Electrical Characteristics (Unless otherwise, Ta= =5V Parameter REFERENCE Reference Voltage Line Regulation Load Regulation UNDER VOLTAGE LOCKOUT (UVLO) Start Threshold Voltage Threshold Hysteresis PROTECTION Over Voltage OSCILLATOR (R =75k , Frequency Duty Cycle CURRENT SENSING INPUT Threshold Voltage OUTPUT DRIVER ...
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... When the chip, temperature rises up to 150 C, the thermal shutdown (TSD) circuit is activated and the output driver turn off, and then turn on again at 125 6mA Vref & output driver 1mA 8.0V H(ST) 1.2V HYS PWM comparator PWM Logic Current amplifier =20[A] M(MAX) FAN8902(KA3902 6.8V TH(ST BAT ...
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... FAN8902(KA3902) 4. Oscillator Component Selection Vref The oscillator timing components can be calculated as follows Vref V = – – fosc = 1.875 Duty = T fosc 100 C For example, if fosc = 25kHz and duty = 95% ...
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... R12 V CMD Slop Compensation 7. Motor Stall Current Limitation FAN8902 V CMD 1 CMD R14 Vref TR2 R11 + VBAT Buffer-OP-amp Logic 12 + PWM COMP FAN8902(KA3902 PWM _ Comparator FAN8902 6 OSC R10 ...
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... FAN8902(KA3902) In the steady state, the terminal voltage on a motor is consisted of a back EMF and the voltage drop on the armarture resistors. When the motor happens to be stalled, the back EMF becomes zero, and the motor current (I maximum values. Therefore the duty of the pin #12 output becomes lower because of the increase of the sense voltage (V voltage ( lowered, then it makes the duty become lower again ...
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... Reduced switch-on time Uncontrolled without the FAN8902 Controlled with the FAN8902 Stalled state , in the application circuit are as follows: I MAX I SRT LINEAR FULL-ON STOP V V SRT MAX V [V] CMD 36[V], the switching device is turned-on again, and the motor is operated. BAT FAN8902(KA3902 BAT 10 ...
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... FAN8902(KA3902) Test Circuit CMD Iout SW 2 Cid VCC OUT CMDa CMDb 10k 1nF 75k 10k VREF ...
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... R12 Current command NC NC R11 R14 BAT CMD CMDa VCC 12 3 CMDb OUT VREF FAN8902(KA3902 R10 ...
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... FAN8902(KA3902) 13 ...
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... FAN8902(KA3902) DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. ...