Diodes ZXLD1322 - Manual (Page 3)

ZXLD1322
ZXLD1322
Document number: DS32166 Rev. 3 - 2
3 of 17
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April 2010
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A Product Line of
Diodes Incorporated
Pin Description
Name Pin # Description
ADJ 1
Adjust input
• Leave floating, or connect to V
REF
to set 100% output current.
• Drive with dc voltage. (50mV<V
ADJ
< V
REF
) 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
N/C 4 Not connected internally (Open circuit)
ISENSE 5
Switch peak current sense pin
• Connect resistor (R
SENSE
) 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 RSENSE to sense emitter current)
EMITTER2 7
COLLECTOR2 8
Switch Collectors (Connect both pins to lower side of coil)
COLLECTOR1 9
N/C 10 Internally connected - Do not connect to external circuitry
M_VIN 11
Input supply to high side current monitor
• Connect output voltage (whichever is higher)
• Connect resistor (R
M
) from this pin to to V
IN
to define nominal average output (LED)
current of 0.1/R
M
VIN 12
Input supply voltage and load side input of high side current monitor.
Connect to sensing resistor RM.
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 V
REF
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)