BQ76200: current load

Sarra Ben othman

Prodigy 50 points

Part Number: BQ76200

With the circuit shown fromTIDA-10030 T, at 12V pump current will be :

R103; 10M, about 1.2 uA load

R105; 10M, about 1.2 uA load

THE QESTION IS : how can i estimate current R100?

over 1 year ago

0 Matt Sunna over 1 year ago

TI__Guru* 77333 points

Hi Sarra,

The current through R100 will normally be close to zero except for when the CHG FET is turning on. Figure 20 of this application report shows the current through the gate resistor during turn on: https://www.ti.com/lit/an/slua794/slua794.pdf

Best regards,

Matt

0 Sarra Ben othman over 1 year ago in reply to Matt Sunna

Prodigy 50 points

the current through the gate resistor according to the figure 20 is 19.6mA which is upper than the current load of charge pump 40uA .. is that normal ?

+1 Matt Sunna over 1 year ago in reply to Sarra Ben othman

TI__Guru* 77333 points

Hi Sarra,

The charge pump charges the charge pump capacitor. When there is ~20mA for around 2us (as shown in Figure 20), this will come from the charge pump capacitor and will not be a problem. Figure 5 in the same document shows how the charge pump voltage looks during FET switching.

Best regards,

Matt

0 Sarra Ben othman over 1 year ago in reply to Matt Sunna

Prodigy 50 points

thank you Matt Sunna

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BQ76200: current load