I am looking for technical information about UC1526J part. Even with datasheet technical document 85515, I don't understand how the component operate and what is the waveform on the output A and output B and the frequency of these output.
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I am looking for technical information about UC1526J part. Even with datasheet technical document 85515, I don't understand how the component operate and what is the waveform on the output A and output B and the frequency of these output.
Hi,
You can refer to Fig 7, 8, and 9 to know the waveforms. Basically the OUTPUT-A and OUTPUT-B are in high or low, like rectangular shape. Fig 8 shows both OUTPUT-A and OUTPUT-B in parallel connection to GND then Vc becomes the driver. Fig 7 and Fig 9 are in push-pull.
Frequency setup is based on page 6, oscillator period vs RT and CT.
CT has a saw tooth waveform to compare to COMP to determine the pulse width. RT CT also generate a pulse to set up the frequency period.
When using CS, the CS threshold will terminate the pulse before the time instant of COMP and CT.
Hello,
Thank you for your reply. The configuration used for my application is exactly the one shown in Fig 7 (push-pull). RT and CT have a value of 13k6 and 1nF respectively, so the oscillator frequency is approximately 133 kHz.
Is the frequency of outputs A and B the same as that of the oscillator?
What is CS used for?
Hi,
OUTPUT-A and OUTPUT-B frequency = fosc/2 (fosc the oscillator frequency)
CS is for current sensing, control and protection.
Hello,
Sorry for the answer delay. Thank you for this answer, this respond to my question. I have a last question, what is the duty cycle of the outputs A & B when the regulated voltage is stabilized?
Hi,
If this is a close loop system operation, the steady state duty cycle will be determined by the feedback loop.
Hi,
These are for max duty. In a close loop system with adequate design, in its steady state the duty cycle is determined by the feedback loop but not reach max duty. If somehow your design reaches max duty then your design needs to modify since after reaches the max duty your Vout won't be able to regulate anymore.
Hi,
No.
A and B both have a similar max duty, but that max duty has a distribution with min that can be as low as 45%.