Document
800mA Buck (Step-down) WLED Driver
SOT-25
Pin Definition: 1. VIN 2. Ground 3. CT 4. ISENSE 5. SW
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TS19373
General Description
The TS19373 is a continuous mode inductive step-down converter, designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The device operates from an input supply between 6V and 40V and provides an externally adjustable output current of up to 800mA. TS19373 includes the output switch and a high-side output current sensing circuit, which uses an external resistor to set the nominal average output current.
Features
● ● ● ● ● ● ● Wide Input Voltage Range 6V~40V 800mA Output Current High Efficiency up to 90% Drives up to 3 (1~3W) LEDs @ VIN 12V Drives up to 7 (1~3W) LEDs @ VIN 24V 180kHz Switching Frequency Internal PWM Filter
Application
● ● ● ● ● DC/DC or AC/DC LED driver applications Back lighting of flat panel displays Signage and decorative LED lightings Chargers LED Lighting Equipment – MR16, Tube
Ordering Information
Part No.
TS19373CX5 RF
Package
SOT-25
Packing
3Kpcs / 7” Reel
Block Diagram
1/7
Version: A09
800mA Buck (Step-down) WLED Driver
Absolute Maximum Rating
Parameter
Input Voltage Supply Voltage (Recommended) FB Voltage SW Voltage Output SW Current Ambient Temperature Range Junction Temperature Range
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TS19373
Symbol
VIN VIN VFB VSW ISW TA TJ
Limit
40 6 ~ 40 -0.3 ~ 40 36 800 -40 to +85 +150
Unit
V V V V mA
o o
C C
Electrical Specifications (Ta = 25oC, unless otherwise noted)
Parameter
Input Voltage Range Line Regulation Charge Current Discharge Current Switching Frequency Current Limit Sense Voltage Switch VCESAT Supply Current Collector off-state Current
Symbol
VIN REGLINE ICHARGE IDISCHARGE FOSC VSENSE VSAT ICC IC(OFF)
Test Conditions
Min
6 --
Typ
-1.4 30 230 180 -1.0 3 1
Max
40 5 45 290 -350 1.3 4 100
Units
V mV uA uA kHz mV V mA uA
VIN =6V~40V VIN =6V~40V CT =100pF, IDISCHARGE = ICHARGE ISW = 300mA VIN =6V~40V, CT =1nF VCE =40V
-180 -250 ---
Note: Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as possible
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Version: A09
800mA Buck (Step-down) WLED Driver
Application Information
Pin Description Pin
1 2 3 4 5
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TS19373
Function
VIN Ground Timing Capacitor ISENSE SW
Description
Input Voltage Supply pin Ground Pin Timing capacitor oscillator input Peak current sense input to monitor the voltage drop across an external resistor to limit the peak current through the circuit Switching Pin. This is the internal Darlington switch collector
Inductor Selection
A 100uH inductor is recommended for most TS19373 applications. Although small size and high efficiency are major concerns, the inductor should have low core losses at 180kHz and low DCR (copper wire resistance).
Diode Selection
Schottky diodes, with their low forward voltage drop and fast reverse recovery, are the ideal choices fo.