CS4525 datasheet(45/91 Pages) CIRRUS

45 / 91 page

DS726A1

CS4525

6.1.7.3

PWM PopGuard Transient Control

The CS4525 uses PopGuard technology to minimize the effects of power-up and power-down output tran-

sients commonly produced by half-bridge, single supply amplifiers implemented with external DC-block-

ing capacitors connected in series with the audio outputs.

PWM PopGuard operates by linearly ramping the PWM power outputs up to and down from their bias

point of VP/2 when a channel is powered up and down respectively using the PDnOutX or PDnAll bits.

This gradual voltage ramp minimizes output transients while the DC blocking capacitor is charged and

discharged.

The PWM PopGuard output ramp time can be varied from approximately 0.70 seconds to approximately

0.85 seconds and can be completely disabled via the RmpSpeed[1:0] bits in the Foldback Cfg register.

All output channels are affected by the RmpSpeed[1:0] bits, and PWM PopGuard is disabled by default.

Referenced Control

RmpSpeed[1:0] ................... “Ramp Speed (RmpSpd[1:0])” on page 70

PDnAll ................................. “Power Down (PDnAll)” on page 81

PDnOutX ............................. “Power Down PWM Power Output X (PDnOutX)” on page 81

CS4525 データシート(PDF) 45 Page - Cirrus Logic