LM5034: To see the max duty of LM5034

Eric Lai

Expert 4940 points

Part Number: LM5034

Hi Expert,

The end customer want to see the max duty of LM5034 for every LM5034 before manufacturing.

They make a test fixture and follow the setting from datasheet Electrical Characteristics stated.

VIN = 48V, VCC1 = VCC2 = 10V externally applied, RT = RDCL = 42.2kΩ, ROVLP =70kΩ, UVLO = 1.5V

COMP1 (COMP2) = open

But not see the max duty of out pin.

Pls advice how to setup to see the max duty of LM5034.

Best regards,

Eric Lai

Field Application Engineer

Texas Instruments Taiwan Limited

O: +886-2-2175-2582

M: +886-909-262-582

E-Mail:Eric.Lai@ti.com

over 4 years ago

0 Teng Feng over 4 years ago

TI__Genius 13660 points

Hi Eric,

The controller duty cycle is determined by the four signals into the 4-input AND gates in Figure 3 (UserMaxDC, MaxDC, PWM and CLK). The output driver pulsewidth is equal to the least of these four pulses. Whichever input of the AND gate transitions high-to-low first terminates the output driver’s on time.

Here, Maximum User Duty Cycle = 80% x RDCL/RT = 80%; MaxDC is around 74% when UVLO = 1.5V.

Do you know what was the maximum duty cycle that customer got under this condition? And it will help to find the reason if you can provide the testing schematic.

Regards,

Teng

0 Eric Lai over 4 years ago in reply to Teng Feng

TI__Expert 4940 points

Hi Teng,

We mail the customer setup info to you.

Kindly advice.