Datasheet

Analog Integrated Circuit Device Data

30 Freescale Semiconductor

10XSC425

5.3 Functional Internal Block Description

Figure 9. Functional Block Diagram

5.3.1 Power Supply

The 10XSC425 is designed to operate from 4.0 to 28 V on the VPWR pin. Characteristics are provided from 6.0 to 20 V for the

device. The VPWR pin supplies power to internal regulator, analog, and logic circuit blocks. The VDD supply is used for Serial

Peripheral Interface (SPI) communication in order to configure and diagnose the device. This IC architecture provides a low

quiescent current Sleep mode. Applying V

PWR

and V

to the device will place the device in the Normal mode. The device will

transit to Fail-safe mode during failures on the SPI or/and on VDD voltage.

5.3.2 High Side Switches (HS0–HS3)

These pins are the high side outputs controlling lamps located for the front of vehicle, such as 65 W/55 W bulbs and Xenon-HID

modules. Those N-channel MOSFETs with 10 m and 25 m R

DS(ON)

are self-protected and present extended diagnostics in

order to detect bulb outage and short-circuit fault condition. The HS output is actively clamped during turn off of inductive loads

and inductive battery line. When driving DC motor or Solenoid loads demanding multiple switching, an external recirculation

device must be used to maintain the device in its Safe Operating Area.

5.3.3 MCU Interface and Output Control

In Normal mode, each bulb is controlled directly from the MCU through the SPI. A pulse-width modulation control module allows

improvement of lamp lifetime with bulb power regulation (PWM frequency range of 100 to 400

Hz) and addressing the dimming

application (day running light). An analog feedback output provides a current proportional to the load current or the temperature

of the board. The SPI is used to configure and to read the diagnostic status (faults) of high side outputs. The reported fault

conditions are: OpenLoad, short-circuit to battery, short-circuit to ground (overcurrent and severe short-circuit), thermal

shutdown, and under/overvoltage. Owing to accurate and configurable overcurrent detection circuitry and wire-harness

optimization, the vehicle is lighter.

In Fail-safe mode, each lamp is controlled with dedicated parallel input pins. The device is configured in Default mode.

Power Supply

10XSC425 - Functional Block Diagram

Parallel Control Inputs

MCU Interface & Output Control

SPI Interface

Self-Protected

Supply MCU Interface & Output Control Self-Protected High Side Switches

PWM Controller

High Side

Switches

HS0-HS3

MCU

Interface