LB11600JV_11 Datasheet, PDF (27/30 Pages) Sanyo Semicon Device – Brushless Motor Predriver IC for Automotive Applications

LB11600JV
5. Hall Input Signals
The Hall effect sensor inputs require input signals with an amplitude larger than the hysteresis (80mV maximum) and an
even larger amplitude is desirable to avoid problems due to noise, phase displacement, and other issues. If disturbances to
the output waveforms (at phase switching) or HP output occur due to noise, the disturbances must be prevented by
inserting capacitors across the inputs or by other means. The Hall inputs are used as input discrimination signals to the
constraint protection circuit and the one-shot multivibrator circuit. Although these circuits are designed to tolerate a
certain amount of noise, care is required if these protection circuits are used. If all three phases of the Hall input signals go
to the same state, all of the outputs will be turned off (all of the UL, VL, WL, UH, VH, and WH outputs will go to the low
level potential).
If the outputs from a Hall IC are used for these inputs, tying one side of the inputs (either the + or - side) to a voltage within
the common-mode input range for when Hall sensors are used allows the other side of the input to be used with an input in
the 0 to VCC range.
6. Undervoltage Protection Circuit
This IC starts up (output operation turns on) at a VCC voltage of 4.3V (typical) and turns the outputs off (sets the UH, VH,
and WH outputs to the low level potential) when the VCC voltage falls to under 3.8V(typical).
7. Constraint Protection Circuit
The LB11600JV includes a constraint protection circuit to protect the motor and the IC itself when the motor is physically
prevented from turning. If the Hall input signals do not change for a certain fixed period when the IC is operating in the
motor drive state, one side of the output system (the UH, VH, and WH outputs) is turned off. The time is set by the
discharge time of the resistor and capacitor connected to the CSD pin. (See the constraint protection circuit timing chart.)
The motor rotation pulse detection signal is detected with the timing of the fall (high to low) of the UH output signal, one
of the three output phases. The rotation pulse detection signal time is set by the discharge time for the CSET pin capacitor.
During motor rotation, the CSD pin potential will always be high during the rotation pulse detection time. If the motor
becomes constrained (stopped), the CSD potential is discharged and the outputs (UH, VH, and WH) are set low when the
CSP potential falls under 0.6V.
After the constraint protection circuit operates, the outputs will be latched in the low state. To clear this latched state, set
either PWMIN or S/S to the high level.
The latched state is cleared when the PWMRE potential falls below 0.55V (typical) and the IC enters the reset state. (See
the latch clear timing chart.)
Note that if the CSD pin resistor Rc is too large, the CSD pin potential may rise due to the bias current from the internal
comparator circuit.
Rotation pulse detection signal time: Tps = Cs × VBE / Icset (s)
Cs:
CSET pin external capacitor (connected between VCC and CSET)
VBE:
VBE for the transistor in the constraint protection circuit: 0.7V (typical)
Lcset:
CSET pin discharge current: 50µA (typical)
Motor constraint time: Tcsd = ln (VCC / (0.6 - Ibcd × Rc) × Cc × Rc (s)
Cc:
CSD pin external capacitor (connected between VCC and CSD)
Rc:
CSD pin external resistor (connected between the CSD pin and ground)
Ibcd:
CSD pin internal comparator bias current: 1µA (typical)
CSD pin discharge potential threshold voltage: 0.6V (typical)
Latch release time: Toff = ln (VCC / 0.55) × Cre × Rre (s)
Cre:
PWMRE pin external capacitor (connected between the PWMRE pin and ground)
Rre:
PWMRE pin external resistor (connected between the PWMRE pin and ground)
CSD potential rise time (rapid charging time): Tchg ≈ Cc × Rc × ln ((V1 - Ic × Rc) / (V2 - Ic × Rc)) (s)
Cc:
CSD pin external capacitor (connected between VCC and CSD)
Rc:
CSD pin external resistor (connected between the CSD pin and ground)
Ic:
CSD pin transistor current (7mA maximum (design target value))
V1:
CSD pin initial voltage
V2:
CSD pin voltage (when the transistor is in the on state): 4.9V (typical)
No.8321-27/30