Datasheet

LMV931-N, LMV931-N-Q1, LMV932-N, LMV932-N-Q1
LMV934-N, LMV934-N-Q1
SNOS993M –NOVEMBER 2001–REVISED NOVEMBER 2013 www.ti.com
TYPICAL APPLICATIONS
HIGH SIDE CURRENT SENSING
The high side current sensing circuit (Figure 29) is commonly used in a battery charger to monitor charging
current to prevent over charging. A sense resistor R
SENSE
is connected to the battery directly. This system
requires an op amp with rail-to-rail input. The LMV931-N/LMV932-N/LMV934-N are ideal for this application
because its common mode input range goes up to the rail.
Figure 29. High Side Current Sensing
HALF-WAVE RECTIFIER WITH RAIL-TO-GROUND OUTPUT SWING
Since the LMV931-N/LMV932-N/LMV934-N input common mode range includes both positive and negative
supply rails and the output can also swing to either supply, achieving half-wave rectifier functions in either
direction is an easy task. All that is needed are two external resistors; there is no need for diodes or matched
resistors. The half wave rectifier can have either positive or negative going outputs, depending on the way the
circuit is arranged.
In Figure 30 the circuit is referenced to ground, while in Figure 31 the circuit is biased to the positive supply.
These configurations implement the half wave rectifier since the LMV931-N/LMV932-N/LMV934-N can not
respond to one-half of the incoming waveform. It can not respond to one-half of the incoming because the
amplifier can not swing the output beyond either rail therefore the output disengages during this half cycle.
During the other half cycle, however, the amplifier achieves a half wave that can have a peak equal to the total
supply voltage. R
I
should be large enough not to load the LMV931-N/LMV932-N/LMV934-N.
Figure 30. Half-Wave Rectifier with Rail-To-Ground Output Swing Referenced to Ground
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