About the output polarity of BUCK-BOOST

zhaoyanhao

About the output polarity of BUCK-BOOST [Copy link]

 

I have been using power chips from TI and ADI, and I know that BUCK-BOOST can both boost and buck voltage. However, I only recently saw that the input and output polarities of BUCK-BOOST are opposite. This is a bit embarrassing. Many chips I have used say that they are BUCK-BOOST, and it is true that they can boost and buck voltage, but they all have the same polarity. What's going on? How can I string this knowledge together?

zhaoyanhao

This chip has four bridges inside, but it is called buck-BOOST. Is it the same as a full bridge?

qwqwqw2088

Buck-BOOST input voltage is higher, lower or equal to the output voltage. This is fine
. Input and output current are intermittent.
The output voltage is a negative voltage
MOS switch tube. The diode terminal voltage is: VIN+VOUT, which has a high voltage resistance requirement for the device.

The principle should be understood from this circuit topology circuit

led2015

In both the Buck-Boost converter and the full-bridge converter, there are four power switches used to achieve forward and reverse current control, but the circuit structures and control signal waveforms of the two are different.

不亦心

Buck-boost generally refers to the step-up and step-down of opposite polarity. Buck&boost is generally used to represent the step-up and step-down of the same polarity.

The one you sent is a four-switch buck-boost, which can be used with the same polarity

zhaoyanhao

qwqwqw2088 posted on 2023-5-30 18:46 It is no problem for the input voltage of buck-BOOST to be higher, lower or equal to the output voltage. The input and output currents are intermittent and the output voltage is a negative voltage MOS switch...

"Output voltage is negative voltage" is still too one-sided

zhaoyanhao

led2015 Published on 2023-5-30 21:06 In both the Buck-Boost converter and the full-bridge converter, there are four power switch tubes used to realize the forward and reverse control of the current, but the circuit structure and control of the two are different.

So it is not appropriate to say that the input and output are reversed when talking about buck-boost