Description

The ML4825CP is a high frequency PWM controller designed for use in Switch Mode Power Supply designs running at frequencies up to 1MHz. It features minimal propagation delays, reliable high frequency operation, and maximized slew rate and bandwidth. The controller can work in either voltage or current mode and offers input voltage feed forward. It includes a 1V threshold current limit comparator for cycle by-cycle current limit and a soft-start cycle initiation at a threshold of 1.4V. The soft start pin also serves as a maximum duty cycle clamp. The controller incorporates an under-voltage lockout circuit with 800mV of hysteresis for low startup current and drives the outputs low. It is similar in architecture and performance to the UC1825 controller, but with additional features.

Specifications and features

- Practical operation at switching frequencies up to 1.0MHz

- High current (2A peak) dual totem pole outputs

- Wide bandwidth error amplifier

- Fully latched logic with double pulse suppression

- Pulse-by-pulse current limiting

- Soft start and maximum duty cycle control

- Under voltage lockout with hysteresis

- Precision trimmed 5.1V bandgap reference

- Pin compatible improved replacement for UC1825

- Fast shut down path from current limit to outputs

- Outputs preset to known condition after under voltage lockout

- Soft start latch ensures full soft start cycle

- Outputs pull low for undervoltage lockout

Application Scenarios

The ML4825CP PWM controller is suitable for use in various Switch Mode Power Supply designs, particularly those requiring high frequency operation up to 1MHz. It can be used in both voltage and current mode applications, and its features make it versatile for different power supply requirements. The controller's ability to provide input voltage feed forward and its soft-start cycle initiation feature also contribute to its application flexibility.

Comparison

- Practical operation at high switching frequencies up to 1.0MHz

- High current dual totem pole outputs for efficient power delivery

- Wide bandwidth error amplifier for accurate signal processing

- Pulse-by-pulse current limiting for optimal current regulation

- Soft start and maximum duty cycle control for smooth startup

- Precision trimmed bandgap reference for stable voltage reference

- Pin compatible improved replacement for UC1825 for easy upgrade

- Outputs pull low for undervoltage lockout, which may affect certain power supply applications