Reducing ACMP Power Consumption

Reducing ACMP Power Consumption

Safety Features Technique

This technique can be used in GreenPAKs that include ACMP’s. The reduction in power consumption will vary.

GreenPAK CMICs are often used in projects to reduce the system’s current consumption. However, several components within GreenPAKs, when active, can cause a noticeable change in current consumption. Amongst the most consumptive macrocells are the analog comparators. Table 1 is taken from the SLG46826 datasheet to highlight the ACMP’s consumption.

Table 1 SLG46826 Current Consumption

 

Luckily, ACMPs can be shut down when not in use. This can be done in two ways:

  1. Through the PWR UP input of the ACMP.
  2. Enabling a Wake-Sleep [WS] counter for the ACMP.

Wake-sleep control requires a dedicated counter configured to WS mode. This is available in many (but not all) GreenPAKs. PWR UP control can be used in any GreenPAK with ACMPs. When the signal is HI the ACMP is on; using logic, counters or other macrocells to turn off the ACMP can drastically reduce power consumption. For example, if two different voltage thresholds are needed the higher-threshold ACMP can be kept inactive until the lower threshold is met.

Figure 15 Common PWR UP Configurations

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