CS4525 View Datasheet(PDF) - Cirrus Logic
Part Name
Description
MFG CO.
CS4525 Datasheet PDF : 98 Pages
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CS4525
gradual voltage ramp minimizes output transients while the DC blocking capacitor is charged and dis-
charged. The Popguard has no effect on the PWM_SIG outputs nor the auxiliary serial output.
+8V to +18V
0.033 uF
VP
RAMP_CAP OUT1
OUT2
CS4525
OUT3
OUT4
Half-
bridge
Filter
Half-
bridge
Filter
Full-
bridge
Filter
Left
Speaker
Right
Speaker
Subwoofer
Figure 19. Popguard Connection Diagram
PWM Popguard is disabled by default; to enable it, the RmpSpd[1:0] register must be set to any value
other than 11. PWM Popguard should only be used for has when the power outputs are configured for
stereo half-bridge with full-bridge sub per Section 6.1.7.1. The RAMP_CAP pin must be connected to the
VP supply through a 0.033 µF capacitor whenever PWM Popguard is enabled, as shown in Figure 19.
VP Voltage
12 V
15 V
18 V
RmpSpd[1:0] = 00
2.16 seconds
1.74 seconds
1.40 seconds
Typical Ramp Up Times
RmpSpd[1:0] = 01 RmpSpd[1:0] = 10
2.20 seconds
2.20 seconds
1.76 seconds
1.78 seconds
1.42 seconds
1.44 seconds
RmpSpd[1:0] = 11
Instant (No Ramp)
Instant (No Ramp)
Instant (No Ramp)
Table 9. Typical Ramp Times for Various VP Voltages
PWM Popguard’s output ramp time will vary depending on the voltage applied to VP and the value of the
RmpSpd[1:0] bits; typical ramp times are listed in Table 9. All output channels are affected by the Rm-
pSpeed[1:0] bits, and PWM Popguard is disabled by default.
Referenced Control
Register Location
RmpSpeed[1:0] ................... “Ramp Speed (RmpSpd[1:0])” on page 75
PDnAll ................................. “Power Down (PDnAll)” on page 89
PDnOutX ............................. “Power Down PWM Power Output X (PDnOutX)” on page 88
6.1.8
Logic-Level PWM Outputs
The CS4525 has two configurable logic-level PWM outputs, PWM_SIG1 and PWM_SIG2. These outputs
can be used as either digital input to an external PWM amplifier such as the CS4412, or as an analog
input to a headphone amplifier or a line-out amplifier.
To eliminate power-up pops when used to supply an external PWM amplifier, the CS4525 implements the
same click-free start-up function on the PWM_SIG outputs as it does for its own powered PWM outputs.
This function can only be utilized if the PWM amplifier has an initial transition delay feature, such as the
CS4412A. To eliminate power-up and power-down pops when used to supply an analog output circuit,
the PWM_SIG outputs support a high-impedance state that is controlled by the HiZPSig bit in the
46
DS726PP1
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