zxld1322 Zetex Semiconductors plc., zxld1322 Datasheet - Page 4

• Manufacturer Part Number: zxld1322
• Description: Buck/boost Mode Dc-dc Converter For Led Driving With 700ma Output And Current Control
• Manufacturer: Zetex Semiconductors plc.

Pin description
Issue 1 - January 2008
© Zetex Semiconductors plc 2008
Name
ADJ
BIAS
CFB
N/C
ISENSE
EMITTER1
EMITTER2
COLLECTOR2
COLLECTOR1
N/C
M_VIN
VIN
TADJ
VREF
Exposed pad
Pin # Description
15
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Adjust input
Bias pin for setting base current of internal switch transistor
Control input/output for feedback control loop
Not connected internally (Open circuit)
Switch peak current sense pin
Switch emitters (Connect both pins to top of R
Switch Collectors (Connect both pins to lower side of coil)
Internally connected - Do not connect to external circuitry
Input supply to high side current monitor
Input supply voltage and load side input of high side current monitor.
Connect to sensing resistor RM.
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
• Drive with low frequency (200Hz) PWM control signal to gate
• Drive with low level dc voltage (VADJ<28mV) to turn off device
• 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
• Connect resistor (Rsense) from this pin to ground to define peak
• Connect output voltage (whichever is higher)
• Connect resistor (R
• Connect thermistor/resistor network to this pin to reduce output
• Connect to VREF to disable thermal compensation function
current from 10% to 100% of set value. (DC brightness control
mode)
output ‘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
average output (LED) current of 0.1/R
current above a preset temperature threshold.
(see section on temperature control for details)
SWPEAK
4
BIAS
M
) from this pin to to VIN to define nominal
) from this pin to ground to reduce base
)=0.05/RS
SENSE
M
to sense emitter current)
ZXLD1322
www.zetex.com