L6362A datasheet(23/37 Pages) STMICROELECTRONICS

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L6362A

Active clamp

DocID027660 Rev 4

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Active clamp

Active clamping is always used in HS and LS configurations. In PP configuration slow

demagnetization is used. Active clamp is also known as fast demagnetization of inductive

loads or fast current decay. When a high-side driver turns off an inductance, a reversed

polarity voltage appears across the load. The OUTH pin is pulled to a voltage below the

ground until it reaches the demagnetization voltage, VCC-Vdemag. The conduction state is

linearly modulated by an internal circuitry in order to keep the OUTH pin voltage at about

VCC -Vdemag until the energy in the load has been dissipated. The energy is dissipated both

in IC internal switch and load resistance. Similarly, in case of load connected between the

LS pin and VCC, at the switch-off (of the low-side switch) the output is pushed to +Vdemag.

See Table 14: "Output stage truth table" for the detailed behavior of the power stage in

different configurations and conditions.

Figure 6: Active clamp equivalent principle schematic. HS configuration (load to GND)

Figure 7: Active clamp equivalent principle schematic. LS configuration (load to VCC)

L6362A

VCC

GND

OUTH

Inductive load

OUTL n.c.

VDEMAG

GIPG020320151227LM

L6362A

VCC

GND

OUTL

Inductive load

VDEMAG

OUTH n.c.

GIPG020320151050LM

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