Microchip Technology PAC1921, Руководство пользователя

Страница: 42 / 57

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.