BU6909AGFT Datasheet, PDF (11/21 Pages) Rohm – Built in HALL element

BU6909AGFT
Datasheet
Low duty start up function
During motor start up from stop condition, outputs are driven by a PWM signal of about PWM 50% duty for 3 times of
changing magnetic direction. After the low PWM duty start up function, output PWM duty changes corresponding to the
input PWM duty. For cases of input PWM duty range of more than 50%, output PWM duty changes corresponding to same
input PWM duty at all driving time. This function enables the IC to start the motor regardless of input PWM signal’s duty.
When input PWM duty is 0%, the motor is held on stand-by mode. Additionally, the motor changes to idling mode for input
PWM duty range of 0% to 2.5%. Idling mode only runs on circuit current 1 (I_CC1) in the Electrical Characteristics table. Idling
mode turns all output terminals to open state.
(a) Case A : Input PWM DUTY 2.5% to 50%
(b) Case B : Input PWM DUTY 50% to 100%
Figure 23. Low duty start up function
Table 1. Truth table of input PWM duty and each outputs terminals
Input PWM duty [%]
IC function (state)
OUT1, OUT2
FG
DUTY 0
OFF (Stand-by mode)
OFF, OFF (Open state)
H (Output Tr : OFF)
DUTY 0 < 2.5
ON (Idle mode)
OFF, OFF (Open state)
H (Output Tr : OFF)
Case A : DUTY 2.5 to 50
(Low duty start up
ON
driving)
H / L, L / H
H/L
Case B : DUTY 50 to 100 ON (Normal driving)
H / L, L / H
H/L
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TSZ22111・15・001
11/18
TSZ02201-0H1H0B101190-1-2
28.Oct.2014 Rev.002