TAIWAN SEMICONDUCTOR TS19370 User Manual
TS19370
SOT-26
General Description
The TS19370 is a step-up DC/DC converter specifically designed to drive white LEDs with a constant current. The
device can drive 2 ~ 9 LEDs in series from a Li-Ion cell. Series connection of the LEDs provides identical LED
currents resulting in uniform brightness and eliminating the need for ballast resistors. The output capacitor can be as
small as 0.22µF, saving space versus alternative solutions. A low 95mV feedback voltage minimizes power loss for
better efficiency. Additional feature include over output voltage limiting when LEDs are disconnected.
The TS19370 switches at a fixed frequency of 1.2MHz, allowing the use of tiny, low profile inductors and capacitors to
minimize footprint and cost in space consideration applications for cellular phone backlighting or other hand held
equipment.
Ordering Information
Part No.
Package
Packing
TS19370CX6 RF
SOT-26
3Kpcs / 7” Reel
Features
● Inherently Matched LED Current
● High Efficiency: 88% Typical
● Drives Up to 6 LEDs @ Vin 5V
● Drives Up to 9 LEDs @ Vin 9~15V
● Over Output Voltage Protection 30V
● Fast 1.2MHz Switching Frequency
● Requires Only 0.22µF Output Capacitor
● PWM dimming control 1KHz to 10KHz
● Analog dimming control
Application
● Cellular Phones
● Portable Electronics Devices PDA, GPS
● LCD Display Module
● White LED Backlighting
Input Voltage vs. Efficiency
Typical Application Circuit
Pin Definition:
1. SW
6. Input
2. Ground
5. OVP
3. Feedback
4. CTRL
Boost (Step-up) WLED Driver with OVP
1/8 Version: D08
Parameter
Symbol
Limit
Unit
Input Voltage
VIN
20
V
Supply Voltage (Recommended)
VIN
2.5 ~ 18
V
FB Voltage
VFB
10
V
SW Voltage
VSW
36
V
CTRL Voltage
V
CTRL
10
V
Ambient Temperature Range
TA
-40 to +85
o
C
Junction Temperature Range
TJ
-40 to +125
o
C
Function Parameter
Symbol
Test Conditions
Min
Typ
Max
Units
Input Voltage Range
VIN 2.5
--
18
V
Feedback Voltage
VFB
ISW=100mA, 66% duty
cycle
86
95
104
mV
FB Pin Bias Current
IB 10
45
100
nA
--
1.9
2.5
mA
Supply Current
IQ
CTRL = 0V
--
0.1
1.0
uA
Switching Frequency
F
RSW
0.8
1.2
1.6
MHz
Switch Current Limit
ICL --
320
--
mA
Maximum Duty Cycle
D
TMX
85
90
--
%
Switch V
CESAT
V
SAT
At ISW= 250mA
--
350
--
mV
Switch Leakage Current
I
LKG
VSW = 5V
--
0.01 5 µA
High
1.5
--
--
V
V
CTRL
V
CTL
Low
--
--
0.4
V
CTRL Pin Bias Current
I
CTL
Ctrl = 2V
--
65
--
µA
Over Voltage Protection
OVP
--
30
--
V
Thermal Resistance
θJA --
220
--
°C/W
Absolute Maximum Rating
TS19370
Boost (Step-up) WLED Driver with OVP
Electrical Specifications (Ta = 25
o
C, VIN= V
=3V, CIN=1uF, C
CTRL
=0.22uF unless otherwise noted)
OUT
Note:
Absolute maximum ratings are limits beyond which damage to the device may occur.
The maximum allowable power dissipation is a function of maximum function temperature, TJ(max), the junction to
ambient thermal resistance, θ JA , and the ambient temperature. The maximum allowable, power dissipation at any
ambient temperature is calculated using: PD(MAX)= [TJ(max)-TA]/θJA . Exceeding the maximum allowable power
dissipation will cause excessive die temperature. All limits at temperature extremes are guaranteed via correlation
using standard statistical methods
2/8 Version: D08
Pin
Function
Description
1
SW
Switching Pin. This is the collector of the internal NPN power switch. Connect to
inductor and diode. Minimize the metal trace area connected to this pin to reduce
EMI.
2
Ground
Ground Pin. Connect directly to local ground plane.
3
Feedback
Feedback Pin. Reference voltage is 95mV. Connect LEDs and a resistor at this pin.
LED current is determined by the resistance and CTRL voltage.
4
CTRL
Shutdown Pin and Dimming Control Pin.
VCTRL > 1.8V generates full-scale LED current
VCTRL < 0.4V chip is off
Switching from 04V to 2.0V, PWM duty cycle controls the LED current
5
OVP
Over Voltage Protection, 30V
6
Input
Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible
Functional Block
TS19370
Boost (Step-up) WLED Driver with OVP
Pin Description
3/8 Version: D08
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