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L5994 - L5994A

The 5V regulator is always active, even if both PWM regulators are disabled, as long as power is applied to the

chip.

The 2.5V reference voltage generator, provides comparison levels for threshold detection and device operation.

It is allowed to source up to 5mA to an external load from its buffered output, externally available through pin

VREF.

The reference voltage generator is active if at least one of the two RUNx signal is asserted.

If either PREG5 or VREF does not deliver the correct voltage, the device is shut down.

Figure 6. Controlled timing sequencies

t

t

t

RUN2

VOUT2

RUN1

t

VOUT1

t

CRST

PWROK1

t

t

t

t

RUN2

VOUT2

H2GATE

t

R2GATE

t

CRST

t

PWROK2

t

RUN1

t

VOUT1

t

H1GATE

t

R1GATE

a) TURN-ON TIMING SEQUENCE

b) SHUTDOWN TIMING SEQUENCE (1)

t

t

t

RUN2

VOUT2

H2GATE

t

R2GATE

t

CRST

t

PWROK2

t

RUN1

t

VOUT1

t

H1GATE

t

R1GATE

c) SHUTDOWN TIMING SEQUENCE (2)

t

H2GATE

t

R2GATE

t

VOUT2

t

PWROK

t

VOUT1

CRST

t

H1GATE

t

R1GATE

d) OVP TIMING SEQUENCE

PWROK2

t

t

PWROK1

t

PWROK1