W-52 Datasheet, PDF (2/11 Pages) Copal Electronics – CMOS White LED Driver

W-52
Typical Application Circuit
VIN
2.7 V
to
4.2 V
C1
4.7 F
L₁ 6.8 H
D1
6
1
VIN
SW
PWM
DIMMING
CONTROL
TSOTï23 Pin Numbers
W-52
5
SHDN
RSET
4
R_SET
1.50 k
3
LED
GND
2
15 mA
C1: Taiyo Yuden JMK212BJ475
C2: Taiyo Yuden EMK212BJ105
D1: Zetez ZHCS400
L1: Sumida CLQ4D106R8
(Panasonic ELJEA6R8)
C2
1F
Figure 1. LiïIon Driver for Four HighïBrightness White LEDs
Table 1. PIN DESCRIPTION
Pin Number
SOT23
Name
Function
1
SW
Switch pin. This is the drain of the internal power switch. For minimum EMI, min-
imize the trace area connected to this pin.
2
GND
Ground pin. Connect pin 2 to ground.
3
LED
LED (cathode) connection pin.
4
RSET
RESET pin. A resistor connected from pin 4 to ground sets the LED current. This
pin is also used to dim the LEDs.
5
SHDN Shutdown pin.
6
VIN
Input supply pin. This pin should be bypassed with a capacitor to ground. A
4.7 F capacitor mounted close to the pin is recommended.
2