LM74610-Q1: disable the T0

Ryuji

Guru 20090 points

Part Number: LM74610-Q1
Other Parts Discussed in Thread: LM74700-Q1, TINA-TI

Hello,

For avoiding Voltage drop during T0, we would like to change schematics as the attached file.
Are there any concern in the attached file?
I add the Diode between FET gate and GATE DRIVE pin for disable the gate sink from GATE DRIVE pin.
And add the Diode from CARTHODE pin to Drain of FET to getting Vf voltage drop for charge pump.
Also, we add the diode and resistor to protect reverse battery.

In my customer ,there is the boost converter after LM74610-Q1 and this voltage drop induce unstable operation of the boost converter.
I appreciate it your support this issue.

snom610_1117.TSC

I have the customer schematics , I can send it if you contact following my e-mail address.

asaka-r@clv.macnica.co.jp

Best Regards,
Ryuji

over 6 years ago

0 Karikalan Selvaraj over 6 years ago

TI__Genius 16305 points

Hi Ryuji

I am looking into the query, will get back soon.

Regards,

Kari.

0 Ryuji over 6 years ago in reply to Karikalan Selvaraj

Guru 20090 points

Hi Kari san,

Thank you for your reply.
Your prompt reply would be appreciated.

Best Regards,
Ryuji

0 Karikalan Selvaraj over 6 years ago in reply to Ryuji

TI__Genius 16305 points

Hi Ryuji,

I have looked at the TINA file and believe that Drain of the MOSFET Q1 should connect with Cathode.

But nevertheless, this is not going to work because of the internal charge pump charging / discharging is designed.

Initially, when the FET is off, body diode voltage drop is used to charge the charge pump. (with the new circuit we have the drop across external diode as well).

As the charge pump reaches 6.3V, it is disabled and FET is turned ON. This Charge pump voltage (across external VCAP) is used for internal biasing as well and hence it discharged slowly. As it discharges and reaches 5.15V, MOSFET is turned OFF by pulling Gate down.

Irrespective of ANODE-CATHODE Voltage, this happens and hence cannot use in the way shown in the schematic.

Regards,

Kari.

0 Karikalan Selvaraj over 6 years ago in reply to Karikalan Selvaraj

TI__Genius 16305 points

Hi Ryuji,

Please have a look at new device LM74700-Q1 which is in preview and this does not have that voltage drop on the output.

Regards,

Kari.

0 Ryuji over 6 years ago in reply to Karikalan Selvaraj

Guru 20090 points

Hello Kari san,

I appreciate your support.
I missed attached TINA-TI file.

Please see the attached image.
Could you please check the schematics of this?
We make voltage drop by external diode.

Also , could you please let me know the schedule of LM74700-Q1?

Best Regards,
Ryuji

0 Ryuji over 6 years ago in reply to Ryuji

Guru 20090 points

Hello Kari san,

The schematics is not operated as expected in test.
Thus, we would like to recommend the LM74700-Q1 to the customer.
Could you please let me know the RTM date of LM74700-Q1?

Best Regards,
Ryuji

0 Karikalan Selvaraj over 6 years ago in reply to Ryuji

TI__Genius 16305 points

Hi Ryuji,

I have replied to your email id.

Regards,

Kari.

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LM74610-Q1: disable the T0