LM5041A: DC-DC converter

liu shilin

Part Number: LM5041A

Hi, I'm an engineer of hardware, and I'm encountering a problem in using LM5041A, and the phenomenon is : when the temperature going up, the HD's PWM become a little larger , but the CS waveform is the same, the COMP pin's voltage is fewer ( FB is connected to gnd). Is this the IC's internal problem ? for I don't know why the COMP pin's voltage is fewer (200 mV lower from 31 degree to 100 degree) the HD's PWM is larger(1.8% larger, the CS pin's voltage is almost the same)

over 7 years ago

0 Peter Meaney over 7 years ago

TI__Mastermind 31580 points

Hi Liu

As the temperature rises the resistance of the copper traces in the PCB and in the transformer will increase so it is likely that the duty cycle and COMP will rise to compensate for higher voltage drop in the PCB and in the output circuit as well.

Regards

Peter

0 liu shilin over 7 years ago in reply to Peter Meaney

Prodigy 40 points

It's the problem of leakage current of diode which in circuit

0 Peter Meaney over 7 years ago in reply to liu shilin

TI__Mastermind 31580 points

Hi Liu,

So have you solved the issue? Is the diode in the control circuit or in the power stage.

Regards

Peter

0 liu shilin over 7 years ago in reply to Peter Meaney

Prodigy 40 points

yes, I have solved it. The diode is in the voltage loop circuit, which leakage current is higher while temp is rising, and the DC working point influenced

0 Peter Meaney over 7 years ago in reply to liu shilin

TI__Mastermind 31580 points

Hi Liu,

Great, well done. Can we close the post now?

Peter

0 liu shilin over 7 years ago in reply to Peter Meaney

Prodigy 40 points

yes

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LM5041A: DC-DC converter