UC3843BD1 datasheet by STMicroelectronics

UC3843BD1 Frequently Asked Questions (FAQs)

• What is the recommended operating voltage range for the UC3843BD1?
  The recommended operating voltage range for the UC3843BD1 is 12V to 28V, with a maximum voltage rating of 30V.
• How do I choose the right resistor values for the oscillator circuit?
  The choice of resistor values for the oscillator circuit depends on the desired switching frequency. A higher resistance value will result in a lower switching frequency, while a lower resistance value will result in a higher switching frequency. A good starting point is to use a 2.2kΩ resistor for a 50kHz switching frequency.
• What is the purpose of the soft-start pin (SS) and how do I use it?
  The soft-start pin (SS) is used to gradually increase the output voltage of the converter during startup, reducing inrush current and electromagnetic interference (EMI). To use the soft-start pin, connect a capacitor from the SS pin to ground and a resistor from the SS pin to the output voltage. The capacitor value should be around 10nF to 100nF, and the resistor value should be around 1kΩ to 10kΩ.
• How do I compensate for the voltage drop across the current sense resistor (RSENSE)?
  To compensate for the voltage drop across the current sense resistor (RSENSE), you can add a voltage offset to the current sense signal. This can be done by adding a voltage source in series with the current sense resistor, or by using an op-amp to amplify the current sense signal.
• What is the maximum current rating of the UC3843BD1?
  The maximum current rating of the UC3843BD1 is 1A, but this can be increased by using an external transistor or MOSFET to boost the current capability.