L99UDL01 datasheet(15/88 Pages) STMICROELECTRONICS

15 / 88 page

DS12511 Rev 5

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L99UDL01

Device description

The 3V3 supply has a low voltage warning function with hysteresis. When the 3V3 regulator

drops below 3V3UV threshold for t3V3UV, timed actuation is halted, the outputs (internal half

bridges and drivers for external MOSFET) are disabled, and the V3V3UV bit is set in the SPI

diagnostic register 13h.

If, for any reason the 3V3 supply falls below V3V3RST_F the Logic State machine and all of

the registers are RESET to their default state and held there.

Upon rising out of V3V3RST_R RESET will be disabled and the L99UDL01 will enter Standby

mode.

The C3V3 pin is intended only for supply to the IC. It is not recommended that the C3V3 pin

is used to power any other circuitry.

2.3

Charge pump

The charge pump uses two external flying capacitors, which are switched with fCP. The

output of the charge pump has a current limitation. In standby mode or after a global thermal

shutdown has been triggered the charge pump is disabled.

Figure 3. Charge pump low filtering and start-up

At coming out of standby the outputs are enabled tSET_CP seconds after the charge pump is

re-enabled as long as the VCPLOW threshold is achieved. The CPLOW bit will remain set,

indicating that the charge pump was low since the last reading of the register.

At any time the charge pump output voltage drops below VCPLOW the CPLOW bit is set and

the internal half bridges and the external H-Bridge MOSFET gate drivers are pulled low.

After a CPLOW event the outputs are re-enabled tCP seconds after the charge pump voltage

rises above VCPLOW. Actuation can be restarted via SPI frame or EN_OUT rising edge

according to configuration registers. In this case the outputs that are actuated by the output

override (OUTx_on) bits will automatically turn back on when the charge pump is above

CPLOW.

An over voltage or under voltage fault (VSovsd, VDDuv, V3V3uv) will disable the charge

pump only while that condition exists. The charge pump will automatically restart once the

over voltage or under voltage fault is no longer present.

In the case of a global TSD event all of the TSD flags must be cleared or the ACT_OFF

control bit must be reset to re-enable the Charge pump.

Any time the charge pump is enabled, re-enabled or restarted the drivers will not be

available until after tset_CP and the charge pump voltage exceeds the VCPLOW threshold

(see Figure 3).

Charge

Pump

VCP_Low

Filter Time

(tcp)

Start-up Blanking

time (tset_CP)

CLK

Power

Stage

Disable

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