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LTC4013 no PWM output

HI, i designed charger with LTC4013, and i have problem to run it.

all 4 UVLO conditions are sucessfull:

Voltage DCIN pin2 = 22V (more than 3,45V)

Voltage ENAB pin 5 = 1,55V (more than 1,2V)

Voltage BST pin21 = 5,02V (more than 4,25V)

Voltage BAT/SENSE pin19 = 4,57V (more than 1,97V)

after all condiotions passed, (more that 17V DC in) the INFET signal turns on, also the 5V reference starts to produce 5V, the current sink is 3mA. No pwm signals from top and bottom gate drivers are visble. I tested 2 different ICs, with the same behavior, the same current sink. I use additional diode to produce "false battery voltage" signal on the BAT pin. What is different is using additional gate driver for MOSFETS,but this circuit i used many times with cooperation with warious ICs and it was no problem with it. With this connection also the V BST is more than 4,35V. FBOC pin is connectd to VCC, NTC also to disable MPPT and NTC features.

please do you have some tips what to test, measure? It is real mystery for me.

Circuit is here. Thank you.

  • Update, for others... LTC starts to produce PWM and wait for the output voltage rise. If the voltage dont rise in some time, it stops. The problem was, that i tested circuit without additional driver voltage and was not able to drive MOSFETS. now it works, on the picture is start up procedure.

  • Hi Janek555, Im having a similar problem to yours where the TG pin does not giving any output to turn ON the Top Mosfet. Can you explain what is the solution? I do not understand your explaination above. Thank you

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