UCC2813-1: UCC2813 Vcc Current

lev nemets1

Part Number: UCC2813-1

Tool/software:

Hello,

Datasheet for UCC2813 has limited value for Vcc current, but it does not say if it is RMS or Average value. As this current has pulsed shape, the difference between RMS and Average is very significant. Could you, please, clarify which value (RMS or Average) should be used in calculation.

Regards

Lev

over 1 year ago

0 Hong Huang over 1 year ago

TI__Guru 73595 points

Hi,

They are DC currents for startup current and operating current which are defined without switching so not pulsed current - you can see the test condition is with VRC = 0.

0 lev nemets1 over 1 year ago in reply to Hong Huang

Intellectual 475 points

Hi, Thank you for reply. I am asking about VCC current specified in p.7.1 (Absolute Maximum Rating). Also what is the difference between this current ans current Ivcc specified in p.7.3 (Recommended Operating Condition).

Thanks

Lev

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0 Hong Huang over 1 year ago in reply to lev nemets1

TI__Guru 73595 points

Hi,

That is max current - no more than that - including spike currents.

0 lev nemets1 over 1 year ago in reply to Hong Huang

Intellectual 475 points

Hi,

Thanks for the very quick reply. This controller allows 1A peak output current. This current can only be sourced from Vcc. You say that the Vcc current limit of 30mA is the maximum current including spikes. Can you, please, explain how the Vcc input can provide 1A peak current to the output and have an input current including spikes of less than 30mA?

Thanks

Lev

0 Hong Huang over 1 year ago in reply to lev nemets1

TI__Guru 73595 points

Hi,

This portion is understood as the current from driver needs ok to produce through VDD but no other currents.

0 lev nemets1 over 1 year ago in reply to Hong Huang

Intellectual 475 points

Hello Hong,

Thank you for reply. I am sorry, but I can not understand your answer. What is VDD? There is no VDD pin or signal in this controller. Did you mean VCC? I simulated this controller using TI SPICE model (see attached waveform for VCC Input current and DRV Output Current). Because VCC Input current contains high peak component and Datasheet gives Absolute Maximum Rating for this current (p7.1, 30mA), my initial question was: Should we measure RMS value or Mean value of this current (30mA is this RMS or Mean)? Could you, please answer this question.

Regards.

Lev

+1 Hong Huang over 1 year ago in reply to lev nemets1

TI__Guru 73595 points

Hi,

yes, Vcc current. The current into Vcc due to DRV is to follow DRV current and is ok to over 30mA. The abs max currently is for any currents other than the DRV current. So when you see Vcc current > 30mA but you in line with DRV then ok.

This would need to check current waveform so not convenient. So practically you can check Vcc DC current to be < 30mA as a rule of thumb. But if the current > 30mA at anytime not due to DRV then not ok.

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UCC2813-1: UCC2813 Vcc Current