bd67929efv ROHM Co. Ltd., bd67929efv Datasheet - Page 6

• Manufacturer Part Number: bd67929efv
• Description: Three-phase Brushless Motor Driver For Polygonal Mirrors [for Lbp, Ppc]
• Manufacturer: ROHM Co. Ltd.

BD67929EFV
© 2010 ROHM Co., Ltd. All rights reserved.
www.rohm.com
○VREG/5V regulator output terminal
○PROCLK/Connection terminal of a capacitor to set the clock cycle for protection
○HB/Bias terminal for Hall element
○FG/FG output terminal
○CS/Current detection comparator input terminal
○U, V, W/Output terminal
This terminal is the connection terminal of capacitor to stabilize the 5V output of internal regulator. It should be connected
with the capacitor (0.01µF-1µF) to the ground. This terminal is used as the regulator to the Hall element too. The road
current should be within 20mA.
This terminal is the connection terminal of capacitor to set the time of detection.
This terminal is the open collector type, and low side switch. By connecting the GND side of Hall element to the HB, the
bias current of the Hall element will be turned off with the SS set to high or open. It is very useful for the low power
consumption because the bias current for Hall element will be 0µA.
This terminal outputs the signal which indicate the rotation count, which is synthesize from Hall signal of U-phase.
This terminal is open drain type output, it should be pulled-up to the external regulator (0-5.5V) through the resistor.
The capability of FG terminal is 15mA maximum, please set the voltage of external regulator and the value of resistor to
be within 15mA.
In this IC, CS terminal, which is the input terminal of current limit comparator, is independently arranged in order to
decrease the lowering of current-detecting accuracy caused by the wire impedance inside the IC of RNF terminal.
Therefore, please be sure to connect RNF terminal and CS terminal together when using in the case of PWM constant
current control. In addition, because the wires from CS terminal is connected near the current-detecting resistor in the
case of interconnection, the lowering of current-detecting accuracy, which is caused by the impedance of board pattern
between RNF terminal and the current-detecting resistor, can be decreased. Moreover, please design the pattern in such
a way that there is no noise plunging. In addition, please be careful because if terminal of RNF is shorted to GND, large
current flows without normal PWM constant current control and, then there is danger that OCP or TSD will operate.
To reduce the PWM noise influence, please out the filter between RNF terminal and CS terminal.
Motor's drive current is flowing in it, so please wires in such a way that the wire is thick & short has low impedance. It is
also effective to add a Shot-key diode if output has positive or negative great fluctuation when large current is used etc.,
for example, if counter electromotive voltage etc. is great. Moreover, in the output terminal, there is built-in clamp
component for preventing of electrostatic destruction. If steep pulse or voltage of surge more that maximum absolute
rating is applied, this clamp component operates, as a result there is the danger of even destruction, so please be sure
that the maximum absolute rating must not be exceeded.
ex.) when C=0.1µF, The period of PROCLK=20m[s]
The cut-off frequency is below
ex.) when C1=330pF, R1=1kHz
The period of PROCLK=C×200k[s]
f = 1 / (2π×R1×C1)
Hall signal
FG
CS
C1
HUP
R1
f=483[kHz]
HUN
R
RNF
RNF
6/14
Technical Note
2010.12 - Rev.A