AME, Inc.

7

AME5107

Rev.A.01

PWM Control 3A Buck

Converter

C

n Detailed Description

PWM Control

The AME5107 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. In converters of

the AME5107, the pulse width varies in a range from 0 to 100%, according to the load current. The ripple voltage

produced by the switching can easily be removed through a filter because the switching frequency remains constant.

Therefore, these converters provide a low-ripple power over broad ranges of input voltage and load current.

Under Voltage Lockout

The under voltage lockout circuit of the AME5107 assures that the high-side MOSFET driver outputs remain in the off

state whenever the supply voltage drops below 3.3V. Normal operation resumes once VCC rises above 3.5V.

RDS(ON) Current Limiting

The current limit threshold is setting by the external resistor connecting from VCC supply to OCSET. The internal

100uA sink current crossing the resistor sets the voltage at the pin of OCSET. When the PWM voltage is less than the

voltage at OCSET, an over-current condition is triggered.

I

See above formula for setting the current limit value.