IRS21171 View Datasheet(PDF) - International Rectifier

Part Name

Description

Manufacturer

IRS21171

SINGLE CHANNEL DRIVER

International Rectifier 

IRS211(7,71,8)(S)

Tolerant to Negative VS Transients

A common problem in today’s high-power switching converters is the transient response of the switch node’s

voltage as the power switches transition on and off quickly while carrying a large current. A typical half bridge

circuit is shown in Figure 5; here we define the power switches and diodes of the inverter.

If the high-side switch (e.g., Q1 in Figures 6 and 7) switches off, while the current is flowing to a load, a current

commutation occurs from high-side switch (Q1) to the diode (D2) in parallel with the low-side switch of the

inverter. At the same instance, the voltage node VS swings from the positive DC bus voltage to the negative

DC bus voltage.

DC+ BUS

Input

Voltage

Q1

D1

VS

Q2

To

Load

D2

DC- BUS

Figure 5: Half Bridge Circuit

DC+ BUS

Q1

D1

OFF

VS

IL

Q2

D2

OFF

Figure 6: Q1 conducting

DC- BUS

Figure 7: D2 conducting

Also when the current flows from the load back to the inverter (see Figures 8 and 9), and Q2 switches on, the

current commutation occurs from D1 to Q2. At the same instance, the voltage node VS swings from the positive

DC bus voltage to the negative DC bus voltage.

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