NXP Semiconductors

19

33982

FUNCTIONAL DESCRIPTION

Functional internal block description

Figure 9. Functional internal block diagram

POWER SUPPLY

The 33982 is designed to operate from 4.0 V to 28 V on the VPWR pin. Characteristics are provided from 6.0 V 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 VPWR and VDD to the device places the device in the Normal mode. The device transits to Fail-safe mode in case of failures on

the SPI (watchdog timeout).

HIGH-SIDE SWITCH: HS

This pin is the high-side output controlling multiple automotive loads with high inrush current, as well as motors and all types of resistive

and inductive loads. This N-channel MOSFET with a 2.0 m

RDS(on), is self-protected and presents extended diagnostics to detect load

disconnections and short-circuit fault conditions. The HS output is actively clamped during a turn-off of inductive loads.

MCU INTERFACE AND OUTPUT CONTROL

In Normal mode, the load is controlled directly from the MCU through the SPI. With a dedicated SPI command, it is possible to

independently turn on and off several loads that are PWMed at the same frequency, and duty cycles with only one PWM signal. An analog

feedback output provides a current proportional to the load current. The SPI is used to configure and to read the diagnostic status (faults)

of high-side output. The reported fault conditions are: open load, short-circuit to ground (OCLO-resistive and OCHI-severe short-circuit),

thermal shutdown, and under/overvoltage.

In Fail-safe mode, the load is controlled with dedicated parallel input pins. The device is configured in default mode.

MCU Interface and Output Control

MC33982 - Functional Block Diagram

Power Supply

Self-protected

High-side Switch

HS

Parallel Control Inputs

Power Supply

MCU Interface and Output Control

SPI Interface

High-side Switch