Regarding to charge pump(LDC_A) on MSP430FG479, my customer is asking some question.
They are using MSP430FG479 for battery application and use LCD_A controller with charge pump..
They configure LCD_A module and charge pump as following at low power mode(LPM3).
(Low power mode :LPM3)
LCD_A module off:(LCDO=0)
Charge pump disable(LCDCPEN=0)
Charge pump voltage select(VLCDx) = 2.96V
In above case, when MSP430 is set to low power mode, power consumption of some MSP430 is became to high.
A ratio of high current consumption against total device(100set) is 10 (set) /100(set). (one MSP430 using/set)
･Normal power consumption(Vcc:3.3V) at LPM3: less than 1uA
･High power consumption(Vcc:3.3V) at LPM3: more than 10uA (40-50uA average)
They found out to cause high power consumption by power voltage(Vcc).
And they confirmed threshold range of power supply(Vcc) with high current consumption MSP430.
Please refer below table.
･NG-min[V]：minimum voltage of increase current consumption
･NG-max[V]：maximum voltage of increase current consumption
･NG-range[mV]：voltage range of increase current consumption
･Above behavior is happened only in above supply voltage range on high power consumption MSP430.
(It isn’t happened except to above supply voltage range.)
･Regardless of supply voltage, above behavior isn’t happened on normal power consumption MSP430.
(1) Is there any possible that this behavior will be caused on regulated charge pump/contrast control in MSP430?
If so, is there any possible cause?
(2) When power supply voltage(Vcc) closes to charge pump set voltage, how behavior does MSP430 become?
(3) Is there any possible that this behavior will be caused by individual specificity of device?.