PWM pulse Generator for LCD Panels - BD9478F

BD9478F is PWM pulse generator for LCD panel. ThisIC compares triangle waveform which is generatedinside IC and external DC signal, and generates aPWM pulse. This PWM pulse is provided to LED driverand controls LED grayscale. PWM pulse frequencycan be synchronized to external signal frequencyinputted to SYNC terminal. Even if this frequency getsout of range, it works in the setting frequency, isprotected and it always provides stable PWM pulse toLED driver.

* This product is a STANDARD grade product and not recommend for on-vehicle devices.
Part number
Unit Quantity
Minimum Package Quantity
Packing Type
BD9478F-GE2 Active SOP8 2500 2500 Taping Yes
Vin(Min.)[V] 4.5
Vin(Max.)[V] 5.5
Operating Temperature (Min.)[°C] -40
Operating Temperature (Max.)[°C] 85
  • ・ The signal that the frequency synchronizes with the VSYNC signal is output to PWMOUT.
    ・ The PWM pulse is generated with the DC signal of a triangular wave and PDIM generated with the LCT capacitor.
    ・ When the VSYNC frequency exceeds the stipulated range, it fixes by a set frequency. (fSYNC fPLL=0.36*fPLLtyp , fSYNC> fPLLtyp*2.75 -> fPLL=2.75*fPLLtyp)
    ・ When VSYNC is a no signal input, the self-oscillation is operated by set frequency decided on the CT capacitance.
    ・ When the pulse signal is input to the terminal EXTPWM, it shifts automatically to external PWM mode.
Technical Data
Application Note

Thermal Resistance