DB64R - Cirrus Logic, Inc.

P r o d u c t I n n o v a t i o n F r o m DB64R

DB64RU 1

Demonstration Board for the SA306-IHZ

DB64R

P r o d u c t I n n o v a t i o n F r o m

http://www.cirrus.com

FEB 2009

APEX − DB64RUREVA

INTRODUCTION

The DB64R is designed to demonstrate the capabilities of the SA306 3 phase brushless DC (BLDC) motor driver

IC. This fully assembled demonstration allows the user to directly control the speed and direction of the motor. An

onboard controller decodes HALL Effect sensor inputs for commutation in either direction and provides four quad-

rant PWM signals to control the power outputs of the SA306. LEDs provide feedback for motor control status and

fault indications. Provisions on the DB64R allow the user to bypass the onboard control circuit and directly interface

with the SA306 brushless motor driver.

The DB64R demonstrates proper layout techniques for the

SA306 high current switching amplier. The economical con-

struction uses only a two-sided PCB and allows the SA306

to deliver peak currents of over 1kW.

THERMAL CONSIDERATIONS

The SA306 is available in a surface mount package which

can deliver peak power of over 1kW. This presents an obvi-

ous and signicant thermal challenge. The DB64R offers a

compact design which can deliver 17A peak current by using

a patent pending mounting technique. Mounting the SA306

in an inverted fashion as shown in Figure 1 reduces the pro-

le height of the assembly and provides a direct interface

between the thermal tab of the PowerQuad package (pack-

age outline drawing HQ) and the small HS33 heatsink. The

DB64R assembly can dissipate 7-9W in still air at 25ºC ambi-

ent temperature, depending on the orientation of the heatsink

ns. To use the DB64R in higher power applications, use a

fan or mount a heatsink with larger thermal mass. Although

the SA306 is rated for operation from -25 to +85ºC, the other

components on the DB64R are limited to 0 to 70ºC ambient

temperature.

CIRCUIT OPERATION

The DB64R control circuit receives power via two terminal

block connections. The Vs connection supplies power to

drive the motor and must be above the under-voltage lock-

out threshold of the SA306, approximately 8.3V. The control

circuit requires 12V for proper operation a regulator on the

DB64R provides the 5V logic supply for the SA306. There

are no special considerations for sequencing the two sup-

plies.

Figure 1 – Mounting Technique

PATENT PENDING

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Figure 2 – User Control Features

Figure 2 shows the user control features of the DB64R.

The PWM duty cycle is controlled with the potentiometer

(1 in gure 2). The power LED (2) will illuminate when the

12V supply is connected. The DB64R will power up with

the SA306 disabled. The enable button (3) will toggle the

SA306 on and off with the LED (4) illuminating to indi-

cate the enable status. Direction of the motor is similarly

controlled with the button (5) and is indicated by the LED

(6).

The DB64R monitors the Temperature warning status pin

of the SA306. If this pin goes high an LED (7) illuminates

and the enable circuit is forced to a disable status. The

temperature LED is not latched and may stay illuminated

only briey while the temperature of the SA306 is above

135ºC. The temperature decrease rapidly via the heatsink

once the SA306 is disabled.

The SA306 current limit feature is set to limit at approxi-

mately 15A to provide a demonstration of the full capabili-

ties of the SA306. An LED (8) will illuminate if the SA306

cycle-by-cycle current limit circuit engages. The thermal and current limit features are robust, but will not protect the

SA306 in all circumstances. The user must consider the worst case thermal and power dissipation conditions.

Hall Effect inputs to connector J3 (9) are required to commutate the motor correctly. Filtering networks and 5V pull-

up are provided for glitch-free operation. The Hall sensor connector, J3 (9), also includes a tachometer output which

is based on the commutation signals from the Hall inputs. Power for the Hall sensors is provided by U2 in gure 3,

an integrated brushless motor controller IC. The controller decodes the Hall sensor inputs and generates six PWM

control signals directly to the SA306. Push-button switches 1 and 2 trigger latches (U4) for direction and enable

control, respectively. Diodes D7 & D8 and resistors R24, 25, 29 & 30 provide a means of bypassing the DB64R

control circuit. The 5V regulator, U3, provides 5V to the SA306, the latches and the status LEDs.

11 7

10 9

P r o d u c t I n n o v a t i o n F r o m DB64R

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Figure 3 – Schematic

ENHANCING & BYPASSING THE DB64R CONTROL CIRCUIT

Connector J5 allows the user to bypass many of the manual control features of the DB64R. A signal generator can

control the duty cycle with a 2.5 to 7.5V signal, overriding the control potentiometer. A rising 5V edge on pin 3 or 4 of

connector J5 will toggle the Direction or Enable latches, respectively. By jumping resistors R24 & R25, the latches

are bypassed completely and the logic signals on pins 3 & 4 will directly control the direction and enable functions of

the DB64R. With these resistors jumped, the direction and enable LEDs will not represent the states of the DB64R

and the pushbuttons will have no effect on the operation. The Temperature disable feature of the DB64R will also

not function, although the LED will continue to provide over-temperature status.

Connector J4 is connected directly to the PWM input pins of the SA306. This connector may be used to monitor

the signals or to bypass the control IC on the DB64R. The enable function is not controlled via these pins, although

pulling all six input pins low provides the same effect. The Enable pushbutton and the connection via J5 are also

effective as previously described. The circuit shown in gure 3 in the dashed box is a simple circuit that allows the

user to monitor and control the enable or direction status remotely. Either feature can be toggled on the falling edge

of the signal at the node labeled TOGGLE.

LAYOUT CONSIDERATIONS

A simple two layer construction is sufcient because of the convenient pinout of the SA306 PowerQuad package.

Input signals are routed into one side of the package and high power output signals are routed from the other side in

2 ounce copper. This eliminates the need to route control signals near motor connections where noise may corrupt

the signals. Filling top and bottom layers with copper reduces inductive coupling from the high current outputs. 1nF

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capacitors with excellent high frequency characteristics bypass the Vs motor supplies on each phase. Two 150μF

electrolytic capacitors provide a local, low inductance source to accommodate surge currents up to 17A. Six 100V

Schottky diodes conduct the commutation current via low forward voltage paths which reduces the power dissipa-

tion in the SA306. These diodes are rated for 5A continuous and are mounted close to the SA306 to reduce induc-

tance in the commutating current loop. For applications with continuous currents less than 5A, the Schottky diodes

may not be necessary if the higher forward voltage internal body diodes and the associated power dissipation are

manageable during commutation cycles.

Figure 4 shows the top and bottom layouts of the DB64R. Gerber les for the circuit board are available upon re-

quest.

Figure 4 – PCB Layout (not to scale)

TOP SIDE

BOTTOM SIDE

3.888”

1.860”

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BILL OF MATERIALS

Designation Description P/N

C1,C18 CAP, 1.0uF, 16V Kemet, C0805C105K4RAC

C13 CAP, 33pF, 50V Kemet C0603C330J5GACTU

C2,C3,C4 CAP, 1.0nF,100V Kemet,C0805C102J1GACTU

C5,C6 CAP, 150uF, 100V Panasonic, EEVFK2A151M

C7,C8,C14,C15,C16 CAP, 0.1uF, 16V GRM188F51C104ZA01D

C9,C10,C11,C12,C17 CAP, 2.2nF, 50V GRM188R71H222KA01D

D1,D2,D3,D4,D5,D6 Diode, 5A Schottky Diodes Inc. DS5100

D7,D8,D9 IN4148 Vishay, 1N4148WS-V-GS08

J3,J4 Conn, 6 pin .100 ctrs Samtec TSM-106-01-T-SV

J5 Conn, 4 pin .100 ctrs Samtec TSM-104-01-T-SV

LED1-5 LED, Red Lite-On LTST-C190CKT

Q1,Q2 XTR, NPN MMBT3904

R1,R2,R3 RES, 470, 5% RK73B1JTTDD471J

R11,R12,R13 RES 2.0K, 1% Vishay,CRCW06032K00FKEA

R24,R25 RES, 6.8K Vishay,CRCW06036K80FKEA

R26,R27 RES, 10K Vishay,CRCW060310K0FKEA

R29,R30 RES, 3.3K Vishay,CRCW06033K30FKEA

R4,R5,R6,R18,R19,R20,R21,R32 RES, 1.0K, 5% RK73B1JTTD102J

R7,R31 RES, 24.9K,1/10W, 1% RK73H1JTTD2492F

R8 POT, 20K muRata, PVG3A203C01

R9,R10,R14,R15,R16,R17,R22,R23 RES, 4.99K Vishay,CRCW06034K99FKEA

SW1,SW2 Pushbutton, SPST-NO Panasonic, EVQ-Q2B01W

TB1,TB2 Term. Blk., 3 pin, 5mm On Shore Tech, OSTTA034163

Thermal Grease Heatsink compound N/A

U1 SA306-IHZ Cirrus Logic, SA306-IHZ

U2 UCC3626 Texas Instruments, UCC3626PW

U3 LM78L05 National Semiconductor, LM78L05ACMX/NOPB

U4 74AC74 Texas Instruments, SN74AC74PW

Heatsink Cirrus Logic, HS33

PCB, 1.75” x 3.75” Cirrus Logic, EVAL67R

Screw, #4-40 x ¼” N/A

Solder Tin/Silver 96/4

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CONTACTING CIRRUS LOGIC SUPPORT

For all Apex Precision Power product questions and inquiries, call toll free 800-546-2739 in North America.

For inquiries via email, please contact tucson.support@cirrus.com.

International customers can also request support by contacting their local Cirrus Logic Sales Representative.

To nd the one nearest to you, go to www.cirrus.com

IMPORTANT NOTICE

Cirrus Logic, Inc. and its subsidiaries ("Cirrus") believe that the information contained in this document is accurate and reliable. However, the information is subject

to change without notice and is provided "AS IS" without warranty of any kind (express or implied). Customers are advised to obtain the latest version of relevant

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supplied at the time of order acknowledgment, including those pertaining to warranty, indemnication, and limitation of liability. No responsibility is assumed by Cirrus

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sent for copies to be made of the information only for use within your organization with respect to Cirrus integrated circuits or other products of Cirrus. This consent

does not extend to other copying such as copying for general distribution, advertising or promotional purposes, or for creating any work for resale.

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Cirrus Logic, Cirrus, and the Cirrus Logic logo designs, Apex and Apex Precision Power are trademarks of Cirrus Logic, Inc. All other brand and product names in

this document may be trademarks or service marks of their respective owners.

DB64R Quick Start Guide

1. Connect the following:

Connection Location Indicator Comment

Vs TB2-3 9-60V

Ground TB2-2

Vctrl TB2-1 LED 2 12V

Motor Phase A TB1-1

Motor Phase B TB1-2

Motor Phase C TB1-3

Hall Sensor A J3-1

Hall Sensor B J3-2

Hall Sensor C J3-3

Hall 5V J3-5 Output from PCB

Hall ground J3-6

2. Apply 12V to Vctrl. LED 2 should light.

3. Apply voltage to Vs based on rated motor voltage, normally 12-48V.

4. Press ENABLE switch 3. LED 4 will light and motor should start.

ORDERING INFORMATION

DB64R Demonstration Board includes one populated EVAL67R PCB and one SA306-IHZ sample