TS19705CX6
Taiwan Semiconductor
5 Version: C1607
APPLICATION INFORMATION
Function Description
TS19705 is constant current control IC with active power factor correction isolated or non-isolated AC-DC LED
lighting control. The TS19705 is configurable as an isolated, primary-side-regulated Flyback controller or non-
isolated Buck-Boost converter for LED lighting applications. The controller is Boundary Conduction Mode (BCM)
operation with constant on time based regulator design to achieve high power factor performance.
The TS19705 has built-in V
CC
over voltage protection, open LED protection, short LED protection, over temperature
protection, primary side current limit and gate clamp functions.
The average output current can be expressed as below.
Where :
I
O_avg
is the average output current
N
P
is the primary-side turn ratio
N
S
is the secondary-side turn ratio
R
S
is the sensing resistor connected between the MOSFET source and the GND
Pin Detail
Compensation
This is the output of the g
m
amplifier. Connect with a suitable RC network to ground.
Ground
GND is the reference node of internal circuit.
Current Sense
MOSFET current signal sensing for multiplication and current limit setting function.
Where :
I
CS
is the input current sence
R
S
is the sensing resistor connected between the MOSFET source and GND
Output
Gate drive for external MOSFET switch and is built-in gate clamp function.
V
CC
Power supply for the controller during normal operation. The controller will start up when V
CC
reaches 18V (typical)
and will shut-down when V
CC
voltage is below 9.5V (typical). A decoupling capacitor should be connected between
the V
CC
and GND pin as close as possible.
The TS19705 performs V
CC
over voltage protection though V
CC
pin. Once V
CC
pin exceeds in 32V, TS19705 turns
off and latchs out the MOSFET switcher until V
CC
goes below V
CC_OFF
.
