charged and the circuit can restart immediately.

This method is suitable when the inverter uses

only one DC blocking capacitor connected to the

power ground, as used on figure 11 for Compact

the UVLO turns off the oscillator and gives the

same bridge configuration.

the UVLO turns off both MOSFETs. An SCR like

the X0202MA may be used for the reset function.

If the current flowing through the supply resistor is

higher than the SCR holding current (see figure

12), the SCR will remain on and the two MOS-

FETs off. Removing power or commutating the

SCR allows a new start up [4].

Otherwise a disable circuitry that turns off the two

MOSFETs (see figure13), can achieve the shut-

down function. Compared to the SCR solution,

the shutdown is immediate and the inverter can

restart on the disable order.

H.V.

L6569

Vs

200

200

100nF

5.6k

VS

BOOT

HVG

OUT

LVG

GND

CF

RF

DISABLE

HCF4011

22

4.7 k W

BC327

Figure 13: L6569 disable circuitry with both MOSFETs off.

L 6569A

Rs

R

R

C

shutdown

OFF

OFF

Figure 12: Shutdown with a thyristor & a serial resistor to slow down the supply voltage decay.

L 6569

ON

R

F

R

L

C

F

AN880 APPLICATION NOTE

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