Datasheet and Circuit Diagram, Posted by: admindata at December 16th, 2009
This UC3825 IC, which is manufactured by Texas Instruments, is a high-speed pulse width modulation (PWM) controller which can be considered as the DC/DC Converter central processor in the following example of controls circuit that is primarily composed of three ICs, the UC3825BN, ISO124, and the IR2110. And here is the controls circuit schematic using The UC3825BN.
The IC has been used in the circuit since it has compatibility with Voltage and Current-Mode topologies, and dual alternating outputs. It adjusts the duty cycle of the high and low side outputs to the IR2110 drivers achieving the 400VDC output which is monitored using the ISO124 chip. The UC3825BN PWM chip also monitors the input current to the DC/DC converter. When the RAMP (pin 7) is connected to the timing capacitor (CT) the UC3825BN acts as a duty cycle control IC.
Or you might see the UC3825BN datasheet here (source: focus.ti.com)