X80200 Datasheet, PDF (9/16 Pages) Intersil Corporation – Power Supply Swquencer with Power-up System Mnitoring

X80200, X80201, X80202, X80203, X80204
VDDH
FAILS
VDDM
FAILS
VDDL
FAILS
SETV
VDDH
GATE_L
REF
FET “L”
DRAIN
(VFB)
REF
t_{DELAY_DOWN}
GATE_M
FIGURE 5. VOLTAGE BASED SEQUENCING OF GATE_M
AND GATE_L
Power Supply Failure Conditions
Should there be a power failure of VDDH, GATE_H,
GATE_M and GATE_L charge pumps are all turned OFF
when VDDH falls below the UVLO_H threshold.
Should there be a failure of the VDDM supply, the GATE_M
charge pump turns off when VDDM falls below the UVLO_M
threshold. After a t_{DELAY_DOWN} time period, the GATE_L
charge pump turns OFF.
Should there be a failure of the VDDL supply, the GATE_L
and GATE_M charge pumps both turn off when VDDL falls
below the UVLO_L threshold.
VDDM
VDDL
GATE_H
GATE_M
GATE_L
t_{DELAY_DOWN}
FIGURE 6. GATE CONTROL DURING INDIVIDUAL POWER
FAIL CONDITIONS
Remote Monitoring Functions
The X80200 can monitor the status of the GATE_H,
GATE_M, and GATE_L charge pump control signals. This
allows an indirect way to monitor system voltages. The
volatile status bits: Stat_GATEH, Stat_GATEM, and
Stat_GATEL indicate the status of GATE_H, GATE_M and
GATE_L output control signals, respectively. If the bit is a “1”,
then the charge pump is being turned on. If the bit is a “0”,
the output is turned off. Since the bits reflect the internal
control signal and not the state of the output, external
loading that prevents the charge pump from reaching the
desired FET gate drive voltage will not be detected by
reading the register.
These status bits can be read via the 2-wire serial bus. Refer
to Status Register section for more information on how to
read this register.
Several X80200 devices can be used to monitor many
system voltages on different system cards on a backplane.
Each X80200 has 3 slave address pins allowing up to 8
X80200 to be used on the same bus.
X80200 provides the user the ability to remotely turn-off the
gates through software. (See "Remote Shutdown Register
(RSR) (Volatile)" on page 10 for more information.)
9
FN8154.0