LMR12010: Enable startup voltage of Vin

xin.zhan yang

Prodigy 30 points

Part Number: LMR12010
Other Parts Discussed in Thread: LM73605, TINA-TI, TPS3710

Hi, I need an application that Vin is the great 9V and IC start work and Vin is less 5V and IC shoutdown.

The R147 change to 301K ohm, R153 change to 68.1K.

The Result:

Startup (CH2:Vin, CH3:Vout, CH4:Ven):

Vin = 6.0V； Ven(UM20_PIN4):1.1V

Shutdown (CH2:Vin, CH3:Vout, CH4:Ven):

Vin = 5.4V； Ven(UM20_PIN4):0.9V

over 7 years ago

0 Anthony F over 7 years ago

TI__Mastermind 35215 points

Hi user,

These measurements show the expected behavior for the LMR12010. The typical EN turn on threshold is ~1.1 V and the typical EN turn off threshold is ~1.0 V. Are you trying to get the LMR12010 to wait until a higher input voltage of 9 V to turn on?

Best Regards,
Anthony

0 xin.zhan yang over 7 years ago in reply to Anthony F

Prodigy 30 points

Hi Anthony,

However I refer specification that Ven_th is the under list.

Ven_th (Max SD Volttage) is 0.4V

Ven_th (Min Enable Voltage) is 1.8V

0 Anthony F over 7 years ago in reply to xin.zhan yang

TI__Mastermind 35215 points

Hi user,

A spec like this means all LMR12010 parts will be disabled when EN<=0.4 V and and all LMR12010 parts will be enabled when EN>=1.8 V.

0 xin.zhan yang over 7 years ago in reply to Anthony F

Prodigy 30 points

Hi Anthony,
How I do it that +5V turn on/off by Enable PIN.
When
Vin > 9V, +5V turn on.
Vin < 6V, +5V turn off.

0 Anthony F over 7 years ago in reply to xin.zhan yang

TI__Mastermind 35215 points

The technique described in the block post I have linked below could be used.

How to add hysteresis to a DC/DC converter

Other Parts Discussed in Post: TINA-TI , LM73605 A version of this post was also published on Electronic Design . Is enable hysteresis not included in the DC/DC converter you are designing with? Or is…

By ReedKacz over 7 years ago in Technical articles > Power management

Alternatively for more accuracy a voltage supervisor with the technique described in the application note I've linked below could be used to do this. The TPS3710 looks like a good simple supervisor for this.

Power management

Power management forum

LMR12010: Enable startup voltage of Vin