Cirrus-logic CRD48L10 Manual do Utilizador descarregar pdf (Página 38)

Chapter 11

Measuring Power

Current measurement points are available for the CS48L10, CS42L73, and for the entire CRD48L10 using the provided

current measurement headers.

Figure 11-1. Current Measurement Points for CS42L73 and CS48L10

Figure 11-2. Current Measurement Point for CRD48L10 Main Power

When shipped, each header has a bypass resistor (either 0.5O or 0.1O) to eliminate the need for shunts. This also allows

the user to make voltage measurements across the pins of each header and use the following formulae to convert those

readings to current.

Measurement Method:

• TP20—Measure voltage across header and multiply by 2 to get current

• TP21—Measure voltage across header and multiply by 2 to get current

• TP23—Measure voltage across header and multiply by 2 to get current

• TP22—Measure voltage across header and multiply by 10 to get current

• P16—Remove shunt; insert current meter in series and measure current

Table 11-1. Power Measurement Headers

Header Voltage Signal Bypass Resistor

TP20 +1.0 V – +1.2 V CS48L10 Core Power Rail R170

TP21 +1.8 V CS48L10/O Power Rail R171

TP22 +4.0 V Battery Voltage for CS42L73 R180

TP23 +1.8 V CS48L73 + 1.8 V Power Rail R192

P16 +4.0 V Main Power Rail for CRD48L10-4in4out N/A

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Cirrus-logic CRD48L10 Manual do Utilizador Página 38