Zxld1320 – Diodes ZXLD1320 User Manual
Page 4
ZXLD1320
© Zetex Semiconductors plc 2008
Pin description
Name
Pin
#
Description
ADJ 1
Adjust input
• Leave floating, or connect to VREF to set 100% output current.
• Drive with dc voltage. (50mV<VADJ< VREF) to adjust output current
from 10% to 100% of set value. (DC brightness control mode)
• Drive with low frequency (200Hz) PWM control signal to gate output
‘on’ and ‘off’ at the PWM frequency. (PWM brightness control mode)
• Drive with low level dc voltage (V
ADJ
<28mV) to turn off device
(Standby mode)
BIAS
2
Bias pin for setting base current of internal switch transistor
• Short pin to ground to define maximum base drive current for
output switch (Maximum output current condition)
• Connect resistor (R
BIAS
) from this pin to ground to reduce base
drive current (Reduced output current condition)
CFB
3
Control input/output for feedback control loop
• Connect 10nF capacitor from this pin to ground to provide loop
compensation
POK
4
Power OK flag output
• Pin is high during normal operation.
• Pin switches low if the switch remains on for more than 500µs (nom)
ISENSE
5
Switch peak current sense pin
• Connect resistor (Rsense) from this pin to ground to define peak
switch current (I
SWPEAK
)=0.05/R
S
EMITTER1
6
Switch emitters (Connect both pins to top of R
SENSE
to sense emitter current)
EMITTER2
7
COLLECTOR2
8
Switch Collectors (Connect both pins to lower side of coil)
COLLECTOR1
9
M_LOAD
10
Load side input of high side current monitor.
Connect to sensing resistor RM.
N/C
11
Not connected locally
VIN
12
Positive supply to device (4-18V) and sensing resistor R
M
• Decouple to ground with capacitor close to device
• nominal average output (LED) current = 0.1/R
M
TADJ
13
Temperature Adjust input for LED thermal compensation
• Connect thermistor/resistor network to this pin to reduce output
current above a preset temperature threshold.
• Connect to VREF to disable thermal compensation function
(see section on temperature control for details)
VREF
14
Internal 0.5V reference voltage output
Exposed Pad
15
Connect to Ground (0V)