AN3399 datasheet(9/24 Pages) STMICROELECTRONICS

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AN3399

Evaluations of circuit with PNP and current limitation

Doc ID 018824 Rev 2

9/24

Evaluations of circuit with PNP and current limitation

2.1

Static characteristics

2.1.1

Standby current

The VS current in OFF state was evaluated for the most recommended circuit of voltage

regulation and current limitation with external PNP transistor (see Figure 1).

The 5V2 voltage regulator was switched OFF by SPI in Active Mode Configuration. There

was observed a small current from V3 output caused by residual voltage of 5V2 voltage

regulator.

●

VS =12V

●

IVs =0.279 mA

●

Iop_out =0.052 mA

●

I3 =0.22mA

●

R1, R2, R3, R4, R5 =10K

This current will be significantly decreased by switching the device in V1stby Mode which

turns OFF the operational amplifier (see Figure 5).

Figure 5.

Removing residual current by turning L99PM62GXP in standby mode

Conclusion

A residual current can be observed in the load in case the reference voltage 5V2 is turned

OFF and L99PM62GXP is maintained on active more.

By turning L99PM62GXP in any standby mode (V1stby or Vbatstby), this residual current

will be removed.

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