STGAP1AS datasheet(26/70 Pages) STMICROELECTRONICS

26 / 70 page

Functional description

STGAP1AS

26/70

DocID029344 Rev 2

7.2

Deadtime and interlocking

When single gate drivers are used in half-bridge configuration, they usually do not allow

preventing cross conduction in case of wrong input signals coming from the controller

device. This limitation is due to the fact that each driver does not have the possibility to

know the status of the input signal of the other companion driver in the same leg. Thanks to

the availability of two input pins with opposite polarity the STGAP1AS allows implementing

an hardware interlocking that prevents cross conduction even in case of wrong input signals

generated by the control unit. This functionality can be achieved by implementing the

connection shown in Figure 5 and by configuring the IN-/DIAG2 pin as input (which is its

default configuration).

Figure 5. HW cross conduction prevention in half-bridge configuration with two

single gate drivers

When such configuration is used, it is also possible to enable the STGAP1AS

programmable deadtime feature, which guarantees that at least a DT time passes between

the turn-off of one driver's output and the turn-on of the other driver. The deadtime value DT

can be programmed through the SPI interface as shown in Table 29 on page 54.

If the deadtime feature is enabled, a counter is started when the input status changes from <

IN- = '1' and IN+ = '0' > to a different combination, which means that the other driver in the

same leg is at the beginning of a turn-off (refer to Figure 6).

Once the counter is started it keeps counting regardless of any input variation until a DT

time has passed, and during this time the driver prevents the turn-on of its output even if the

controller tries to force the turn-on (inputs set to < IN- = '0' and IN+ = '1' >).

Once the programmed DT counter is expired, the driver immediately turns the output on as

soon as a turn-on command is present at the input pins, and no extra delay is added.

μC

HIN

LIN

IN+

IN-

gapDRIVE HS

IN+

IN-

gapDRIVE LS

STGAP1AS 数据表(PDF) 26 Page - STMicroelectronics

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