TS19720

Taiwan Semiconductor

Document Number: DS_P0000210

5

Version: B15

APPLICATION INFORMATION

Start-up Current

value of start-up resistor and then reduce the power dissipation.

Under Voltage Lockout (UVLO)

A hysteresis UVLO comparator is implemented in TS19720. The turn-on and turn-off thresholds level are fixed at

17.5V and 8V respectively. This hysteresis shown in Fig.3 ensures that the start-up capacitor will be adequate to

supply the chip during start-up. For quick start-up of the LED driver, the start-up resistor should be matched with

the start-up capacitor.

Leading-Edge Blanking (LEB)

Each time the power MOSFET is switched on, a turn-on spike will inevitably occur at the sense resistor. To avoid

fault trigger, a 400ns 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 cannot switch off the gate driver.

Gate Clamp

Driver is clamped to 12.5V by an internal clamping circuit to avoid the Gate of MOSFET to get damaged.

Over Current Protection (OCP)

The TS19720 has built-in cycle by cycle over current protection function on CS pin. As the CS pin voltage is larger

working in an auto-recovery mode as shown in Fig. 4.

Fig. 4

Fig.3