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PAC1921 High-Side Current/Power Sensor Evaluation Board User’s Guide

DS50002376A-page 42

 2015 Microchip Technology Inc.

4.4.2

Power Free-Run Integration Example

This section provides steps to experiment with free-run integration in SMBus mode and

see the effects of filtering, resolution and sampling. It starts by showing the fastest

integration period and progressively shows higher accuracy.

1. Press the <F2> function key on the keyboard. This performs Quick Setup, which

checks the “READ/INT OVR” box, the “INT_EN” bit box and the “Enable DC

Vsense- Stimulus” box, enables the “Enable Auto INT_EN” control and sets

“MUX_SEL” to VPOWER free-run. Integration begins using the 1 sample default.

2. In the Main Configuration section, click the “I_RES” and “V_RES” boxes so 11-bit

shows; this lowers the resolution from 14 bits to 11 bits.

3. In the Main Configuration section, uncheck the “VSENSE FILT_EN” and “VBUS

FILT_EN” boxes to disable the ADC post filters.

4. In the EVB Demo Configuration section, type 40 mV in the “DC Vsense-

Stimulus” spin box.

5. Observe the plots on the Vbus & Vsense tab, as shown in Figure 4-22, adjusting

the Y-axis values as desired. These settings result in the shortest integration

period.

FIGURE 4-22:

Free-Run Integration, Shortest Period.

PAC1921 Datasheet(PDF) 42 Page - Microchip Technology