L99MC6 datasheet(12/55 Pages) STMICROELECTRONICS

12 / 55 page

Description

L99MC6

12/55

Doc ID 16523 Rev 1

Description

2.1

Dual power supply: VS and VCC

The supply voltage VCC (3.3 V/5 V) supplies the whole device. In case of power-on (VCC

increases from undervoltage to VPOR OFF = 2.7 V, typical) the circuit is initialized by an

internally generated power-on reset (POR). If the voltage VCC decreases under the

minimum threshold (VPOR ON = 2.4 V, typical), the outputs are switched-off (high-

impedance) and the status registers are cleared (see Figure 4).

Figure 4.

Power-on reset

2.1.1

Channels

The channels 1 to 3 are self configuring high-side or low-side n-channel mosfets. This

flexibility allows the user to connect loads in high-side or low-side configuration in any

combination.

In order to provide low Rdson values for high-side configured switches (channels 1 to 3), a

charge pump (CP) to drive the internal gate voltage(s) is implemented. If the charge pump is

activated (ENCP1 = 1, DISCP2 = 0, see Section 9.3: Control and status registers), the

internal charge-pump uses VS from the drain of channel 1, as its power source. Otherwise

VCC is used to drive all channels.

The channels 4 to 6 are n-channel low-side drivers. The source of the respective mosfet are

internally connected to the device GND.

Caution:

For any high-side configuration, channel 1 must be used as a high-side switch.

If channel 1 is configured as low-side, the charge pump has to be deactivated to avoid

charge pump current from the drain.

Caution:

The charge pump may not be deactivated (see Section 9.3: Control and status registers) if

one of the channels is in high-side configuration, while a short-circuit from the source to the

battery is present. If these conditions occur, the voltage of the shorted source is applied to

the VCC pin.

VPOR hyst.

IC is disabled

All Status Registers are cleared

VPOR OFF

VPOR ON

VCC

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