MC33886DH Просмотр технического описания (PDF) - Motorola => Freescale

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MC33886DH

5.0 A H BRIDGE

Motorola => Freescale 

Freescale Semiconductor, Inc.

SYSTEM/APPLICATION INFORMATION

INTRODUCTION

Numerous protection and operational features (speed,

torque, direction, dynamic braking, and PWM control), in

addition to the 5.0 A current capability, make the 33886 a very

attractive, cost-effective solution for controlling a broad range of

fractional horsepower DC motors. A pair of 33886 devices can

be used to control bipolar stepper motors in both directions. In

addition, the 33886 can be used to control permanent magnet

solenoids in a push-pull variable force fashion using PWM

control. The 33886 can also be used to excite transformer

primary windings with a switched square wave to produce

secondary winding AC currents.

As shown in Figure 1, Simplified Internal Block Diagram,

page 2, the 33886 is a fully protected monolithic H-Bridge with

Fault Status reporting. For a DC motor to run the input

conditions need be as follows: D1 input logic Low, D2 input logic

High, FS flag cleared (logic High), with one IN logic Low and the

other IN logic High to define output polarity. The 33886 can

execute dynamic braking by simultaneously turning on either

both high-side MOSFETs or both low-side MOSFETs in the

output H-Bridge; e.g., IN1 and IN2 logic High or IN1 and IN2

logic Low.

The 33886 outputs are capable of providing a continuous DC

load current of 5.0 A from a 40 V V+ source. An internal charge

pump supports PWM frequencies up to 10 kHz. An external

pull-up resistor is required for the open drain FS terminal for

fault status reporting.

Two independent inputs (IN1 and IN2) provide control of the

two totem-pole half-bridge outputs. Two disable inputs (D1 and

D2) are for forcing the H-Bridge outputs to a high impedance

state (all H-Bridge switches OFF).

The 33886 has undervoltage shutdown with automatic

recovery, active current limiting, output short-circuit latch-OFF,

and overtemperature latch-OFF. An undervoltage shutdown,

output short circuit latch-OFF, or overtemperature latch-OFF

fault condition will cause the outputs to turn OFF (i.e., become

high impedance or tri-stated) and the fault output flag to be set

Low. Either of the Disable inputs or V+ must be “toggled” to

clear the fault flag.

The short circuit/overtemperature shutdown scheme is

unique and best described as using a junction temperature-

dependent active current “fold back” protection scheme. When

a short circuit condition is experienced, the current limited

output is “ramped down” as the junction temperature increases

above 160°C, until at 175°C the current has decreased to about

2.5 A. Above 175°C, overtemperature shutdown (latch-OFF)

occurs. This feature allows the device to remain in operation for

a longer time with unexpected loads, while still retaining

adequate protection for both the device and the load.

FUNCTIONAL TERMINAL DESCRIPTION

PGND and AGND

Power and analog ground terminals. The power and analog

ground terminals should be connected together with a very low

impedance connection.

Fault Status (FS)

This terminal is the device fault status output. This output is

an active Low open drain structure requiring a pull-up resistor to

5.0 V. Refer to Table 1, Truth Table, page 14.

V+

V+ terminals are the power supply inputs to the device. All V+

terminals must be connected together on the printed circuit

board with as short as possible traces offering as low

impedance as possible between terminals.

V+ terminals have an undervoltage threshold. If the supply

voltage drops below a V+ undervoltage threshold, the output

power stage switches to a tri-state condition and the fault status

flag is set and the Fault Status terminal voltage switched to a

logic Low. When the supply voltage returns to a level that is

above the threshold, the power stage automatically resumes

normal operation according to the established condition of the

input terminals and the fault status flag is automatically reset

logic High.

IN1, IN2, D1, and D2

These terminals are input control terminals used to control

the outputs. These terminals are 5.0 V CMOS-compatible

inputs with hysteresis. The IN1 and IN2 independently control

OUT1 and OUT2, respectively. D1 and D2 are complimentary

inputs used to tri-state disable the H-Bridge outputs.

When either D1 or D2 is set (D1 = logic High or D2 = logic

Low) in the disable state, outputs OUT1 and OUT2 are both tri-

state disabled; however, the rest of the device circuitry is fully

operational and the supply IQ(standby) current is reduced to a few

milliamperes. Refer to Table 1, Truth Table, and STATIC

ELECTRICAL CHARACTERISTICS table, page 5.

MOTOROLA ANALOG INTEGRATED CIRFCoUrITMDEoVrIeCEIDnAfoTArmation On This Product,

Go to: www.freescale.com

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