IRS2336D International Rectifier Corp., IRS2336D Datasheet - Page 31

• Manufacturer Part Number: IRS2336D
• Description: High Voltage 3 Phase Gate Driver Ic
• Manufacturer: International Rectifier Corp.

Also when the V phase current flows from the inductive load back to the inverter (see Figures 28 and 29), and Q4
IGBT switches on, the current commutation occurs from D3 to Q4. At the same instance, the voltage node, V
swings from the positive DC bus voltage to the negative DC bus voltage.
However, in a real inverter circuit, the V
swings below the level of the negative DC bus. This undershoot voltage is called “negative V
The circuit shown in Figure 30 depicts one leg of the three phase inverter; Figures 31 and 32 show a simplified
illustration of the commutation of the current between Q1 and D2. The parasitic inductances in the power circuit from
the die bonding to the PCB tracks are lumped together in L
V
the circuit.
freewheeling diode due to the inductive load connected to V
flows from the DC- bus (which is connected to the COM pin of the HVIC) to the load and a negative voltage between
V
S1
S1
and the DC- Bus is induced (i.e., the COM pin of the HVIC is at a higher potential than the V
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is below the DC+ voltage by the voltage drops associated with the power switch and the parasitic elements of
Figure 26: Q1 conducting
Figure 28: D3 conducting
When the high-side power switch turns off, the load current momentarily flows in the low-side
OFF
OFF
OFF
ON
Q1
Q2
Q3
Q4
DC+ BUS
DC+ BUS
V
DC- BUS
V
DC- BUS
S1
S2
D3
D2
D4
I
U
I
V
S
voltage swing does not stop at the level of the negative DC bus, rather it
31
C
S1
and L
(the load is not shown in these figures). This current
E
for each IGBT. When the high-side switch is on,
Figure 27: D2 conducting
Figure 29: Q4 conducting
OFF
OFF
OFF
ON
Q1
Q2
Q3
Q4
DC+ BUS
DC+ BUS
V
DC- BUS
V
DC- BUS
IRS2336xD Family
S1
S2
D1
D3
D2
I
U
I
V
© 2008 International Rectifier
S
transient”.
S
pin).
S2
,