7.2.1 Design Requirements

Table 7-1 lists the parameters for this typical application.

Table 7-1. Design Requirements

PARAMETER

VALUE

Nominal DC link voltage

48V

Linear voltage sensing range (VFSR)

60V

Voltage drop across the sensing resistor (RSNS) for a linear response

1V

Maximum current through the resistive divider, ICROSS, at linear full-scale voltage

100µA

7.2.2 Detailed Design Procedure

The 100μA cross-current requirement at the maximum system voltage (60V) determines that the total

impedance of the resistive divider is 600kΩ. The impedance of the resistive divider is dominated by R1, thus

neglecting the voltage drop across RSNS for a moment is acceptable. The closest value to 600kΩ from the E96

series is 604kΩ. This value is for R1.

The linear full-scale input voltage (VFSR) of the AMC0136 is 1V. RSNS is sized to produce a 1V drop at the

maximum system voltage of 60V. RSNS is calculated as RSNS = VFSR / (VDC-link, max – VFSR) × R1. The resulting

value is 10.24kΩ and the closest value from the E96 series is 10.2kΩ.

Table 7-2 summarizes the design parameters for this application.

Table 7-2. Design Summary

PARAMETER

VALUE

R1 resistor value

604kΩ

Sense resistor value (RSNS)

10.2kΩ

Resulting current through resistive divider (ICROSS at 60V)

97.7μA

Resulting full-scale voltage drop across sense resistor (RSNS)

996mV

Total power dissipated in resistive divider

5.9mW

AMC0136

SBASAZ0A – AUGUST 2024 – REVISED DECEMBER 2024

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