TS19340CS14

Taiwan Semiconductor

6

Version: B1705

APPLICATION INFORMATION

Function Description

The TS19340 is a secondary-side CC/CV shunt regulator for LED lighting dimming application. It has a built-in 3.3V

low drop-out voltage (VD pin) for external dimming control. The LED current setting level for PWM and linear

functions can be adjusted by the CCH (maximum), CCL (minimum), and CCO (cut-off) pins. When LED current is

cut-off, the IC will change the CV reference voltage (2.53V

1.21V) and the SWO will be pulled low.

Figure 5: LED Current Ratio vs. PWM Duty Ratio

Figure 6: LED Current Ratio vs. Linear Dimming Voltage

Pin Detail

Pin 1: VD

Pin 2 : CCH

The CCH pin is for the constant current high limit function. The pin function is shown in Figure 5 and Figure 6. The

functional working voltage range is from 3.2V to 0V. The pin connects to internal 5V reference voltage or high

voltage level when the function is not used.

The LED high limit current is shown as follows:

)

( A

R

16

V

I

S

CCH

Limit)

LED(High

×

=

Pin 3: CCL

The CCL pin is for the constant current low limit function. The pin function is shown in Figure 5 and Figure 6. The

functional working voltage range is from 3.2V to 0V. The pin connects to ground when the function is not used.

The LED low limit current is shown as follows:

)

( A

R

16

V

I

S

CCL

Limit)

LED(Low

×

=

Pin 4: CCO (PWM / Linear)

The CCO pin is for the LED current cut-off function. The pin function is shown in Figure 5 and Figure 6. The

functional working voltage range is from 3.2V to 0V. The pin pulls to ground when the function is not used.

The LED cut-off current is shown as a formula following:

)

( A

R

16

V

I

S

CCO

Off)

LED(Cut

×

=