Vansco VMM3120, User Manual

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34 VMM3120
Outputs

The amplifier that measures the sensed current has an allowable voltage range
of 0 V to 3 V. The application software will protect the circuit from an
overcurrent or short-circuit event when the voltage from the amplifier reaches
2.9 V; therefore, the actual usable voltage range from the amplifier is only 0 V
to 2.8 V.
The following table provides specifications for the VMM3120's low-side outputs:
Low-Side Output Specifications
Item MIN NOM MAX UNIT
Switchable voltage range 0 - 32 V
Output current 0 - 2.5 A
Output on state resistance - 50 -
mΩ
Load resistance (24 V system) 10.7 - -
Ω
Current sense amp range 0 - 2.8 V
Overcurrent trip point - 2.9 - V
Current sense resolution - 10 - bit
Current sense accuracy - - 5 %
Current sense resistance 0.1 - -
Ω
Overvoltage - - 36 V
PWM frequency - - 500 Hz
PWM resolution - - 0.1 %
Inductive pulse protection - - 628 V (peak)
4.2.2. Low-Side Outputs with Current Sense Configuration
The low-side outputs with current sense (LS_OUTPUT_1 to LS_OUTPUT_4) are
configured as follows:

The resistor used for sensing current maximizes the accuracy of the current
measurement. The resistor value is 0.1 Ω.

The gain in the amplifier circuit that is used for current sensing maximizes the
accuracy of the current measurement. The gain on the amplifier is 10.

You can configure a 2-pole low-pass filter, which is used for sensing current,
so that it reduces noise in the current measurement.