TS19702 Datasheet, PDF (4/9 Pages) Taiwan Semiconductor Company, Ltd – High Power Factor Corrector LED Driver

Application Circuit
TS19702
High Power Factor Corrector LED Driver
Application Information
Start-up Current
The typical start-up current is around 8uA. Very low start-up current allows the PWM controller to increase the
value of start-up resistor and then reduce the power dissipation on it.
UVLO (Under Voltage Lockout)
A hysteresis UVLO comparator is implemented in TS19702, then the turn-on and turn-off thresholds level are fixed
at 15V and 8V respectively. This hysteresis shown in Fig.11 ensures that the start-up capacitor will be adequate to
supply the chip during start-up. For quickly startup the LED driver, the start-up resistor should be matched with the
startup capacitor. Due to the low UVLO on level, so the turn-on delay time will also never greater than the general
PWM IC.
Oscillator
The maximum duty-cycle of internal oscillator is up to 90% for driving high LED voltage string. The frequency of the
oscillator is fixed to 45KHz by internal setting.
LEB (Leading-Edge Blanking)
Each time the power MOSFET is switched on, a turn-on spike will inevitably occur at the sense resistor. To avoid
fault trigger, a 410ns leading-edge blanking time is built in. Conventional RC filtering can therefore be omitted.
During this blanking period, the current-limit comparator is disabled and can not switch off the gate driver.
4/9
Version: A12