3/20

Datasheet

Datasheet

BD62012FS

TSZ02201-0828ABB00020-1-2

© 2013 ROHM Co., Ltd. All rights reserved.

15.MAR.2013 Rev.003

http://www.rohm.com

TSZ22111 · 15 · 001

 Functional Descriptions

1) Commutation logic

When the hall cycle is about 5-Hz or less (e.g. when the motor starts up), the commutation mode is 120° square wave

drive with upper and lower switching (no lead angle). The controller monitors the hall cycle, and switches to 150°

commutation drive when the hall cycle reaches or exceeds about 5-Hz over four consecutive cycles. Refer to the timing

charts in figures 7 and 8.

2) Duty control

lead angle). The VSP pin is pulled down internally by a 200 k

Ω resistor. Therefore, note the impedance when setting the

VSP voltage with a resistance voltage divider.

3) Carrier frequency setting

The carrier frequency setting can be freely adjusted by connecting an external

resistor between the RT pin and ground. The RT pin is biased to a constant

voltage, which determines the charge current to the internal capacitor. Carrier

frequencies can be set within a range from about 16 kHz to 50 kHz. Refer to

the formula to the right.

4) FG signal output

The number of FG output pulses can be switched in accordance with the number

of poles and the rotational speed of the motor. The FG signal is output from the FG

pin. The 12-pulse signal is generated from the three hall signals (exclusive NOR),

and the 4-pulse signal is the same as hall U signal. It is recommended to pull up

FGS pin to VREG voltage when malfunctioning because of the noise.

5) Direction of motor rotation setting

The direction of rotation may be switched by the CCW pin. When CCW pin is “H”

or open, the motor rotates at CCW direction. When the real direction is different

from the setting, the commutation mode is 120° square wave drive (no lead angle).

It is recommended to pull up CCW pin to VREG voltage when malfunctioning

because of the noise.

6) Hall signal comparator

The hall comparator provides voltage hysteresis to prevent noise malfunctions. The bias current to the hall elements

We recommend connecting a ceramic capacitor with value from 100 pF to 0.01 µF, between the differential input pins of

the hall comparator. Note that the bias to hall elements must be set within the common mode input voltage range

Table 1. 120° commutation (Six-state) truth table

HU

HV

HW

UH

VH

WH

UL

VL

WL

H

L

H

L

PWM

L

H

PWM

--------------------

L

H

L

L

L

L

PWM

H

L

PWM

--------------------

H

H

L

L

L

PWM

L

H

PWM

--------------------

L

H

L

PWM

L

L

PWM

--------------------

H

L

L

H

H

PWM

L

L

PWM

--------------------

L

H

L

L

H

L

PWM

L

L

PWM

--------------------

H

400

=

Ω]

FGS

No. of pulse

H

12

L

4

CCW

Direction

H

CCW

L

CW