LM2623: EN/VDD/BOOT connection consult under 14Vout condition

Stanley Dai

Part Number: LM2623
Other Parts Discussed in Thread: TPS61288

Hi Team,

Customer wanna use our LM2623 to achieve 14Vout, but our BOOT pin can only sustain 10V_max. Customer wants to use external 3.3V to supply power for BOOT pin. Is that okay for doing this? Below is the first version schematic. Thanks.

Best,

Stanley.

over 4 years ago

0 Zack Liu over 4 years ago

TI__Mastermind 34231 points

Hi Stanley,

May I know the input voltage range? What's the maximum Iout of this applicaition.

TI has lots of new boost converter which are more suitable.

0 Stanley Dai over 4 years ago in reply to Zack Liu

TI__Expert 5810 points

Hi Zack,

I will check the details and back to u. But can you review my initial request firstly? Is that okay to do that for connecting BOOT with external 3.3V?

0 Stanley Dai over 4 years ago in reply to Zack Liu

TI__Expert 5810 points

Hi Zack,

Input voltage will be 2~3.8V, output voltage should be 14V with 0.3A.

+1 Zack Liu over 4 years ago in reply to Stanley Dai

TI__Mastermind 34231 points

Hi Stanley,

It's ok to use external 3.3V to supply BOOT pin. Please also note that the VDD pin, EN pin voltage is suggested in the range of 3V ~ 5V. VDD pin should not be connected to the central point of feedback network.

Besides that, I'm afraid LM2623 current capability is not high enough to support 2~3.8V Vin, 14V,0.3A output application. It will trigger the device switch current limit.

TPS61288 could be alternative part.

Power management

Power management forum

LM2623: EN/VDD/BOOT connection consult under 14Vout condition