2.2 LCD Charge Pump Low-Power (Low-Current) Mode

The LCD charge pump can be configured to operate in Low-Power (Low-Current) mode or in Normal Mode, depending upon the application. The setting for this configuration can be determined based upon the V_DD voltage present in the application. When V_DD is ensured to always be above 2.2V during LCD operation, the charge pump can be configured to operate in Low-Power (Low-Current) mode. This is done by setting the LPEN bit of the LCDVCON1 register (LPEN = 1). In instances where V_DD is always ensured to be above 2.2V during normal operation, the voltage does not need to be boosted as much as a V_DD voltage lower than 2.2V would need to be. This allows one of the charging stages (capacitors) to be bypassed from the internal circuitry of the charge pump, and in turn, directly decreases the overall power consumption from the LCD charge pump.

In instances where V_DD is not ensured to maintain a voltage level above 2.2V during LCD operation, the charge pump should be configured to operate in Normal mode to ensure that the voltages are boosted to the proper level. This can be done by clearing the LPEN bit of LCDVCON1 (LPEN = 0). It is recommended that the charge pump is configured to operate in Low-Power (Low-Current) mode to ensure maximum contrast on the display when possible.