AN2758
Application note
EVAL6226QR demonstration board using a dual full-bridge L6226Q for motor control applications
Introduction
This application note describes the demonstration board of the DMOS dual full-bridge L6226Q designed for motor control applications. The board implements a typical application that can be used as a reference design to drive two-phase bipolar stepper motors with currents up to 1A DC, multiple DC motors and a wide range of inductive loads.
Thanks to the small footprint of the L6226Q (QFN 5 x 5 mm, 32-lead) the PCB is very compact (27 x 24.5 mm).
January 2009 |
Rev 2 |
1/8 |
www.st.com
Demonstration board description |
AN2758 |
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Table 1. |
EVAL6226R pin connections |
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Type |
Function |
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VS |
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Power supply |
Bridge A and bridge B power supply |
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PGND |
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Ground |
Power ground terminal |
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IN1A |
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Logic input |
Bridge A logic input 1 |
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IN2A |
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Logic Input |
Bridge A logic input 2 |
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ENA |
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Logic input |
Bridge A enable (active high). When low, the power DMOSs |
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of bridge A are switched OFF. |
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IN1B |
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Logic input |
Bridge B logic input 1 |
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IN2B |
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Logic input |
Bridge B logic input 2 |
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ENB |
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Logic input |
Bridge B enable (active high). When low, the power DMOSs |
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of bridge B are switched OFF. |
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Bridge A overcurrent detection and thermal protection pin. |
DIAGA |
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Open drain output |
An internal open drain transistor pulls to GND when |
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overcurrent on bridge A is detected or in case of thermal |
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protection. |
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Bridge B overcurrent detection and thermal protection pin. |
DIAGB |
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Open drain output |
An internal open drain transistor pulls to GND when |
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overcurrent on bridge B is detected or in case of thermal |
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protection. |
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SGND |
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Ground |
Signal ground terminal |
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OUT1A |
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Power output |
Bridge A output 1 |
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OUT2A |
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Power output |
Bridge A output 2 |
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OUT1B |
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Power output |
Bridge B output 1 |
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OUT2B |
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Power output |
Bridge B output 2 |
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AN2758 |
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Demonstration board description |
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Figure 2. |
EVAL6226QR demonstration board description |
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ENA |
IN2A IN1A DIAGA |
PGND VS |
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OUT1A |
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OUT2A |
SGND
OUT2B
OUT1B
ENB IN1B IN2B DIAGB
The INx input pins drive the corresponding half-bridge. When low logic level is applied the low side MOS is switched on, whereas a high logic level turns on the high side MOS.
Pins ENA and ENB are used to implement overcurrent and thermal protection when connected respectively to the outputs DIAGA and DIAGB.
The output current detection thresholds are selected by the resistor connected between the IC dedicated pins and ground.
Table 2 summarizes the electrical specification of the application and Figure 3 shows the electrical schematic.
Table 2. |
EVAL6226QR electrical specification (recommended value) |
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Parameter |
Value |
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Supply voltage range (VS) |
8 to 52 Vdc |
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RMS output current rating (OUTx) |
up to 1.4 A |
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Switching frequency |
up to 100 kHz |
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Input and enable voltage range |
0 to + 5 V |
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OCD pins voltage range |
-0.3 to 10 V |
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Operating temperature range |
-25 to +125°C |
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L6226Q thermal resistance junction to ambient |
42°C/W |
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