UCC3581 is a voltage mode pulse width modulator designed to control low power isolated DC-DC converters, primarily used for single switch forward and flyback converters. It features BiCMOS circuitry for low startup and operating current, while being able to drive power MOSFETs at frequencies up to 100kHz. The UCC3581 oscillator allows programming of both the frequency and the maximum duty cycle with two resistors and a capacitor. It includes programmable soft start circuitry, overcurrent detection, a 7.5V linear preregulator for controlling chip VDD during startup, and an on-board 4.0V logic supply. The UCC3581 provides functions to maximize light load efficiency that are not normally found in PWM controllers.
The document describes the UCC1581, UCC2581, and UCC3581 voltage mode pulse width modulators designed for low power isolated DC-DC converters, such as those used in Subscriber Line Power (ISDN I.430). These controllers feature BiCMOS circuitry for low startup and operating current, capable of driving power MOSFETs at frequencies up to 100kHz. Key features include programmable minimum and maximum duty cycles with cycle skipping, an output current capability of 1A peak source and sink, and programmable soft start and oscillator frequency.
| Startup Current | 85 µA |
|---|---|
| Operating Current | 300 µA |
| Output Current | 1A Peak Source and Sink |
| Maximum Frequency | 100kHz |
| Reference Output Voltage | 4.0V |
| Supply Voltage | 15V |
| Operating Temperature (UCC1581) | -55°C to +125°C |
| Operating Temperature (UCC3581) | 0°C to +70°C |
The startup current is 85 µA.
The output current capability is 1A peak source and sink.
The typical operating current is 300 µA.
The controller can drive power MOSFETs at frequencies up to 100kHz.