UNISONIC TECHNOLOGIES CO., LTD
UM612/A
LINEAR INTEGRATED CIRCUIT
SPS SECONDARY-SIDE CC/CV
CONTROLLER
DESCRIPTION
The UTC UM612/A is a secondary-side CC/CV controller for
SPS applications.
It integrates a Constant Current (CC) regulating amplifier, a
Constant Voltage (CV) regulating amplifier, and 2 precision
reference voltages.
An internal 2.5V reference voltage is generated from VCC input
power. The UTC UM612/A can be used to monitor the
transformer secondary-side output voltage by the CV control loop
and regulate the output current by the CC control loop at the
same time.
The transformer secondary-side output voltage can be
monitored by the FB pin voltage. The sensed FB pin voltage is
compared with the 2.5V internal reference. When the FB pin
voltage is higher than 2.5V, the OUT pin will sink more current at
the external opto-coupler and instruct the controller at
primary-side to adjust the output voltage.
The output current can be regulated by the voltage across the
CN and CP pins through the current sense resistor connected
between the CN and CP pins. The voltage difference between CN
and CP pins is compared with the 60mV / 30mV internal
reference. When the voltage difference between CN and CP pins
is greater than 60mV / 30mV, the OUT pin will sink more current
at the external opto-coupler and instruct the controller at
primary-side to adjust the output current.
FEATURES
* Secondary-Side Constant Voltage (CV) and Constant
Current (CC) Control
* 4.75V to 50V Operation Voltage Range
* 0.6mA Quiescent Current
* ±1% Output Voltage Accuracy at Full Temperature Range
* Smooth Transition Between CC and CV Control Loops
* -5V Negative Voltage Tolerance at CP pin
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