Data Sheet

LT4322

analog.com

Rev. 0

20 of 29

Very High Input Reverse Voltage Blocking

The LT4322 can withstand reverse battery voltages on its VSSA input due to its floating architecture, as long as the

CATHODE and VDDC pin voltages never exceed 60V with respect to VSSA. For example, in Figure 31, the VIN1 and VIN2

inputs can be safely connected to reverse voltages as high as (VOUT – 60V). The use of a high-voltage depletion MOSFET

to protect CATHODE, as shown in Figure 23, along with an appropriately rated power MOSFET, extends the maximum

tolerable reverse voltage rating to the BVDSS ratings of the MOSFETs. This feature is especially useful in high-voltage

DC diode-OR applications; if a high-voltage battery is plugged in backwards, no damage is done to the system, and

the diode-OR output voltage is not perturbed.

TYPICAL APPLICATIONS

Figure 30. DC Diode-OR Application Circuit: Flyback Circuitry Provides Refresh Power to Floating-Ideal Diode Architecture

VIN1

VOUT

VIN2

SW

RFB

M1

BUK7M15-60EX

CVDDA1

4.7µF

M2

BUK7M15-60EX

CVDDA2

4.7µF

R1

1 kΩ

D1

MBRS360

22µF

C3

D2

1N4148

D3

MMSZ5252BT1G

T1

SUMIDA

12387-T041

CG1

10nF

CG2

10nF

COUT

300µF

GATE CATHODE

VSSA

VDDA

VDDC

ANODE

LT4322

GATE CATHODE

VSSA

VDDA

VDDC

ANODE

LT4322

SW

VIN

EN/UVLO

RFB

LT3001

GND

4V TO 32V

4V TO 32V

NEGATIVE VOLTAGE PROTECTION

VIN(NEG) = VOUT +

– 0

3A

LOAD

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