L99DZ320 datasheet(46/146 Pages) STMICROELECTRONICS

46 / 146 page

Functional description

3.1

Supply VS, VSREG

VSREG supplies voltage regulators V1 and V2, all internal regulated voltages for analog and digital functionality,

LIN, CAN, and two of P-channel high-side switches (HS15 and HS0).

All other high-sides and the charge pump are supplied by VS. In case of VSREG pin disconnected, all power

devices connected to VS are automatically switched off.

Filtering capacitors on VS and VSREG lines must be dimensioned to ensure transient slopes < 100 mV/µs.

3.2

Voltage regulators

The L99DZ320 contains two fully protected low drop voltage regulators, which are designed for very fast transient

response and do not require electrolytic output capacitors for stability.

3.2.1

Voltage regulator V1

The V1 voltage regulator provides 5 V supply voltage and up to 250 mA continuous load current to supply the

system microcontroller and the integrated CAN transceiver. The V1 regulator is embedded in the power

management and fail-safe functionality of the device and operates according to the selected operating mode. The

V1 voltage regulator is supplied by pin VSREG.

In addition, the V1 regulator supplies the device internal loads. The voltage regulator is protected against overload

and overtemperature. An external reverse current protection has to be provided by the application circuitry to

prevent the input capacitor from being discharged by negative transients or low input voltage. Current limitation of

the regulator ensures fast charge of external bypass capacitors. The output voltage is stable for ceramic load

capacitors ≥ 1 µF.

In case the device temperature exceeds the TSD1 threshold the V1 regulator remains on. Hence, the

microcontroller has the possibility for interaction or error logging. If the chip temperature exceeds TSD2 threshold

(TSD2 > TSD1), V1 is deactivated and all wake-up sources (CAN, LIN, EI1, EI2 and timer) are disabled. After

tTSD, the voltage regulator restarts automatically. If the restart fails 7 times within one minute the L99DZ320 enters

the forced VBAT-standby mode. The status bit Forced_Sleep_TSD2_V1SC is set.

3.2.2

Voltage regulator V2

The voltage regulator V2 is supplied by pin VSREG and can supply additional 5 V loads such as sensors or

potentiometers.

Voltage regulator V2 is tracker of V1 regulator. i.e. provides a 5V output that tracks the V1 regulator output voltage

with ΔVo (C.038) accuracy.

Load current of V2 can be up to 50 mA.

The V2 regulator is protected against:

•

overload

•

overtemperature

•

short-circuit (short to ground and battery supply voltage)

•

reverse biasing

3.2.3

Voltage regulator failure

The V1 and V2 regulator output voltages are monitored.

In case of a drop below the V1, V2 fail thresholds (V1,2 < V1,2fail, for t > tV1,2fail), the failure bits V1FAIL, V2FAIL

(SR7) are latched. The fail bits can be cleared by a dedicated SPI command.

3.2.4

Short to ground detection

At turn on of the V1 and V2 regulators, a short to GND condition is detected by monitoring the regulator output

voltage.

If V1 (V2) is below the V1fail (V2fail) threshold for t > tV1short (t > tV2short) after turn on, the L99DZ320 identifies a

short-circuit condition at the related regulator output and the regulator is switched off.

In the case of V1 short to GND, the device enters VBAT-standby mode automatically.

L99DZ320

Functional description

DS14235 - Rev 5

page 46/146

L99DZ320 データシート(PDF) 46 Page - STMicroelectronics

L99DZ320 データシート(HTML) 46 Page - STMicroelectronics

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

データシートダウンロード