MM912F634CV2AP datasheet(59/335 Pages) FREESCALE

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Functional Description and Application Information

Power Supply

MM912F634

Freescale Semiconductor

4.4

Power Supply

The MM912F634 analog die supplies VDD (2.5 V), VDDX (5.0 V), and HSUP, based on the supply voltage applied to the VS1

pin. VDD is cascaded of the VDDX regulator. To separate the High Side outputs from the main power supply, the VS2 pin does

only power the High Side drivers. Both supply pins have to be externally protected against reverse battery conditions. To supply

external Hall Effect Sensors, the HSUP pin will supply a switchable regulated supply. See Section 4.10, “Hall Sensor Supply

Output - HSUP".

A reverse battery protected input (VSENSE) is implemented to measure the Battery Voltage directly. A serial resistor (RVSENSE)

is required on this pin. See Section 4.22, “Supply Voltage Sense - VSENSE". In addition, the VS1 supply can be routed to the

ADC (VS1SENSE) to measure the VS1 pin voltage directly. See Section 4.23, “Internal Supply Voltage Sense - VS1SENSE".

To have an independent ADC verification, the internal sleep mode bandgap voltage can be routed to the ADC (BANDGAP). As

this node is independent from the ADC reference, any out of range result would indicate malfunctioning ADC or Bandgap

reference. See Section 4.24, “Internal Bandgap Reference Voltage Sense - BANDGAP".

To stabilize the internal ADC reference voltage for higher precision measurements, the current limited ADC2p5 pin needs to be

connected to an external filter capacitor (CADC2p5). It is not recommended to connect additional loads to this pin. See

Section 4.19, “Analog Digital Converter - ADC".

The following safety features are implemented:

•

LBI - Low Battery Interrupt, internally measured at VSENSE

•

LVI - Low Voltage Interrupt, internally measured at VS1

•

HVI - High Voltage Interrupt, internally measured at VS2

•

VROVI - Voltage Regulator Over-voltage Interrupt internally measured at VDD and VDDX

•

LVR - Low Voltage Reset, internally measured at VDD

•

LVRX - Low Voltage Reset, internally measured at VDDX

•

HTI - High Temperature Interrupt measured between the VDD and VDDX regulators

•

Over-temperature Shutdown measured between the VDD and VDDX regulators

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