The DC-DC circuit of Lingte LT3780 is shown in the figure. Who can analyze the specific working principle?

QWE4562009

The DC-DC circuit of Lingte LT3780 is shown in the figure. Who can analyze the specific working principle? [Copy link]

The DC-DC circuit of Lingte LT3780 is shown in the figure. Who can analyze the specific working principle?

qwqwqw2088

Powered by 6 lithium battery packs,

For this circuit, you must read the 3780 manual carefully and understand its pinout.

The four MOSFETs are controlled by four pins respectively.
Pins TG1 and TG2 control the gates of the two upper MOSFETs.
Pins BG1 and BG2 control the gates of the two lower MOSFETs.

The rest of the pins are clearly shown in the manual, for example, the INTVcc pin is the output of the internal 6 V low-dropout regulator. It also powers the control circuit and MOSFET drive circuit inside the LTC3780 controller.

The two pins of SENSE+ and SENSE- are connected to the overcurrent sensing resistor

skaler1

Which country is Lingte from? The chip spacing of the Americans is not the same now.

qwqwqw2088

skaler1 posted on 2020-8-5 10:40 Which country is Lingte from? The chip spacing of the Americans is not used now

Linear Technology was acquired by Analog Devices Semiconductor

maychang

qwqwqw2088 on the second floor is right. You should read the LT3780 manual carefully first.

Aren't you asking about "synchronous rectification" and "synchronous boost"? Both are used here.

QWE4562009

qwqwqw2088 posted on 2020-8-5 11:24 Lingte was acquired by Analog Devices Semiconductor

right

QWE4562009

qwqwqw2088 posted on 2020-8-5 09:55 6-string lithium battery pack power supply, this circuit must read the 3780 manual carefully, just understand its pins. The four MOS tubes are controlled by four pins respectively...

If it is a full-bridge drive motor, I can understand the upper and lower ends. I really don't understand what you said about the upper and lower MOS. If you have time, please explain the principle roughly. Buck-boost

qiushenghua

QWE4562009 posted on 2020-8-5 15:05 If it is a full-bridge drive motor, I can understand the upper and lower ends. I really don’t understand the upper and lower MOS you mentioned here. Do you have any...

Full-bridge Buck-Boost actually puts Buck and Boost in one framework.

Borrowing the picture above, replace the motor with an inductor to describe it:

Q3 is normally on, Q4 is normally off, and Q1/Q2 work alternately to form a Buck circuit.

When Q1 is turned on, the inductor stores energy, and when Q2 is turned on, the current continues to flow.

Q1 is normally on, Q2 is normally off, and Q3/Q4 work alternately, forming a Boost circuit.

When Q4 is turned on, the inductor stores energy, and when Q3 is turned on, the output is boosted.

Supplementary content (2020-8-17 10:56): To add, the above analysis is based on the input on the left and the output on the right. Since the circuit structure is mirrored, the input/output can actually be reversed, thereby controlling the direction of the current.