MM912F634CV2AP datasheet(150/335 Pages) FREESCALE

150 / 335 page

Functional Description and Application Information

Supply Voltage Sense - VSENSE

MM912F634

Freescale Semiconductor

150

4.22

Supply Voltage Sense - VSENSE

NOTE

Due to internal capacitor charging, temperature measurements are valid 200 ms (max) after

system power up and wake-up.

The reverse battery protected VSENSE pin has been implemented to allow a direct measurement of the Battery level voltage.

Bypassing the device VSUP capacitor and external reverse battery diode will detect under-voltage conditions without delay. A

series resistor is required to protect the MM912F634 analog die from fast transients.

Figure 41. VSENSE Module

The voltage present on the VSENSE pin can be routed via an internal divider to the internal Analog Digital Converter or issue an

interrupt (LBI) to alert the MCU.

For the interrupt based alert, see Section 4.4, “Power Supply". For VSENSE measurement using the internal ADC see

Section 4.19, “Analog Digital Converter - ADC".

4.23

Internal Supply Voltage Sense - VS1SENSE

In addition to the VSENSE module, the internal VS1 supply can be routed to the analog digital converter as well. See

Section 4.19, “Analog Digital Converter - ADC" for details on the acquisition.

Figure 42. VS1Sense Module

4.24

Internal Bandgap Reference Voltage Sense - BANDGAP

The internal reference bandgap voltage “bg1p25sleep” is generated fully independent from the Analog Digital Converter

reference voltages. Measuring(134) the “bg1p25sleep” reference through the ADC-CH14 allows should return a conversion result

within ADCH14 under normal conditions. Any result outside the range would indicate faulty behavior of either the ADC chain or

the 2p5sleep Bandgap circuity.

Note:

134. The maximum allowed sample frequency for Channel 14 is limited to fCH14. Increasing the sample frequency above can result in

unwanted turn off of the LS drivers due to a false VREG over-voltage.

VS1

VSENSE

VS2

Prescaler

RATIOVSENSE

CH11

ADC

RVSENSE

LBI

VS1

VSENSE

VS2

ADC

RVSENSE

LVI

Prescaler

RATIOVS1

CH12

MM912F634CV2AP Datasheet(PDF) 150 Page - Freescale Semiconductor, Inc

MM912F634CV2AP Datasheet(HTML) 150 Page - Freescale Semiconductor, Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL