what is this concept - vclk?

[usyusy]

what is this concept - VCLK (a pin namely "PWR_5V3D3V_VCLK" on 3v/5v IC) and for what purpose does it serve? any fellow can guide, the schematic page attached .,.,regards

[mon2]

Re: what is this concept - vclk?

It is better to study such cases from all angles. You did not post the details of from which this partial schematic was extracted.

1) Found the tab in your Adobe viewer screen grab.

2) You are reviewing the Latitude 3330 logic board.

3) Found the logic board schematic -> searched for VCLK -> the schematic you have posted is linked to the TI TPS51225. We are lucky that this TI part is available to the public so the datasheet is available.

4) Then search for the 'VCLK' label and found the full details on page # 14.

VCLK = output generated by the TI part and is a 260khz clock used for a charge pump voltage rail. Charge pumps are a low current boosting circuit to allow for a low voltage to create a higher voltage.

For example, on RS232 (aka serial port) transceiver chips, the Vin for the actual IC is +3v3 but they use CHARGE PUMP designs to double or triple the Vin to create a voltage swing of ~6v or even ~9v at the outputs of the transceivers. Being somewhat wimpy rails, they cannot supply too much current and often a few mA. The effort is based on the caps that act as the doubler or more for Vin relationship. Another example is the backlight power rail for LCD panels which takes in ~12v yet produces 25-50 volts for the output.

Ok to use for low current LEDs but do not expect it to power your cooling fan..

See attached.

PS: Next time, share more details so we can all save time in such reviews.

[usyusy]

Re: what is this concept - vclk?

ok sir so nice and thank your for your concept clearance