OUT

1

NŸ

DESAT

GND2

NC

15V

1 F

CLAMP

3

1,8

5

4

6

2

7

15

9,16

11

10

12

13

14

IN-

IN+

RDY

10k

10k

0.1 F

GND1

3V-5.5V

10R

220

pF

ISO5451

FLT

RST

1

NŸ

DESAT

GND2

15V

1 F

220

pF

CLAMP

3

1,8

5

4

6

2

7

15V

15

9,16

11

10

12

13

14

IN-

IN+

RDY

RST

10k

10k

FLT

0.1 F

GND1

3V - 5.5V

10R

1 F

NC

OUT

ISO5451

ISO5451

SLLSEO1B – JUNE 2015 – REVISED DECEMBER 2015

www.ti.com

Typical Applications (continued)

10.2.1 Design Requirements

Unlike optocoupler based gate drivers which need external current drivers and biasing circuitry to provide the

input control signals, the input control to the ISO5451 is CMOS and can be directly driven by the microcontroller.

Other design requirements include decoupling capacitors on the input and output supplies, a pullup resistor on

the common drain FLT output signal, and a high-voltage protection diode between the IGBT collector and the

DESAT input. Further details are explained in the subsequent sections. Table 2 shows the allowed range for

Input and Output supply voltage, and the typical current output available from the gate-driver.

Table 2. Design Parameters

PARAMETER

VALUE

Input supply voltage

3-V to 5.5-V

15-V to 30-V

15-V to 30-V

0-V to 15-V

Output current

2.5-A

10.2.2 Detailed Design Procedure

10.2.2.1 Recommended ISO5451 Application Circuit

The ISO5451 has both, inverting and non-inverting gate control inputs, an active low reset input, and an open

drain fault output suitable for wired-OR applications. The recommended application circuit in Figure 42 illustrates

a typical gate driver implementation with Unipolar Output Supply and Figure 43 illustrates a typical gate driver

implementation with Bipolar Output Supply using the ISO5451.

A 0.1-

reliable operation. The 220 pF blanking capacitor disables DESAT detection during the off-to-on transition of the

gate resistor limits the gate charge current and indirectly controls the IGBT collector voltage rise and fall times.

The open-drain FLT output and RDY output has a passive 10-k

Ω pull-up resistor. In this application, the IGBT

gate driver is disabled when a fault is detected and will not resume switching until the micro-controller applies a

reset signal.

Figure 42. Unipolar Output Supply

Figure 43. Bipolar Output Supply

22

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