zxld1320 Zetex Semiconductors plc., zxld1320 Datasheet - Page 4

• Manufacturer Part Number: zxld1320
• Description: Buck Mode Dc-dc Converter For Led Driving With 1.5a Output And Current Control
• Manufacturer: Zetex Semiconductors plc.

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