25

23

Ex_UVP

PVDD_LD

InternalPVDD

AMP Enable

Comparator

Comparator

20

PVDD_HP

1.25V

Bandgap

(

)

UVP

R11 + R12

V

= 1.25 V

R12

´

Hysteresis

R11

V

= 5 A × R13 ×

+1

R12

æ

ö

ç

÷

è

ø

25

Ex_UVP

R12

R11

External

Sense

Voltage

1.25V

Bandgap

Comparator

R13

DRV604

5 mA

in

in

in

in

in

in

1

1

fc

=

C

=

2

R

C

2

fc

R

p

p

´

´

´

´

DRV604

www.ti.com

SLOS659 – JANUARY 2010

The selected thresholds can be determined as follows:

(1)

(2)

With the condition R13 >> R11||R12

To filter supply spikes and noise a capacitor across R12 can be added.

Input-Blocking Capacitors

DC input-blocking capacitors are required to be added in series with the audio signal into the input pins of the

DRV604. These capacitors block the DC portion of the audio source and allow the DRV604 inputs to be properly

biased to provide maximum performance. The input blocking capacitors also limit the DC gain to 1, limiting the

DC-offset voltage at the output.

Equation 1. For this calculation, the capacitance used is the input-blocking capacitor and the resistance is the

input resistor chosen from Table 1, then the frequency and/or capacitance can be determined when one of the

two values are given.

(3)

Copyright © 2010, Texas Instruments Incorporated

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