LB11823M Datasheet, PDF (16/19 Pages) Sanyo Semicon Device – Direct PWM Drive Brushless Motor Predriver for OA Products

LB11823M
6. Drive method
The output duty can be controlled according to any of following methods.
• Control with the V_CTL pin voltage
For the control voltage, refer to the electric characteristics. For control with the VCTL pin, set the PWMIN pin voltage
to the L level.
• Control with the voltage applied to the TOC pin
The TOC pin voltage and PWM oscillation waveform are compared to determine the output duty. The output duty
becomes 0 % when the TOC pin voltage exceeds V_OH (PWM) (3.0 Vtyp) and 100% when it becomes lower than the
V_OL (PWM) (1.2 Vtyp). For control with the TOC pin, set the PWMIN pin voltage to the L level.
For control with the input level other than the internal CTL amp control input level, external connection of amp allows
setting to the arbitrary input level (with the external amp output connected to the TOC pin). For control from the TOC
pin, fix the V_CTL pin voltage.
For an application in which the regulated voltage is applied to the TOC pin through resistor division, etc., it is
necessary to take into account the effect of resistor (about 20 kΩ) incorporated between the TOC pin and CTL amp
output. (Variation about ±20%, temperature characteristics about +0.3%/°C). If the noise is included in the voltage to
be applied to the TOC pin, chattering may occur in the output. In this case, stabilization with a capacitor is necessary.
• Pulse control with the PWMIN pin
The output can be controlled on the basis of duty obtained by entering the
pulse in the PWMIN pin. The output can be turned ON when the L-level
input voltage is applied to the PWM pin and OFF when the H-level input
Pin PWMIN
voltage is applied. With the PWMIN pin open, the output becomes the H
level and is turned OFF. If input with reversed logic is necessary, addition
of external Tr (NPN) may be enough.
For control with the PWMIN pin, set the V_CTL pin voltage that is more than
the V_CTL2 voltage (output duty set to 100%) or connect the TOC pin to
GND.
Pulse input
7. Hall input signal
The Hall input requires the signal input with an amplitude exceeding the hysteresis width (50 mV max). Considering
the effect of noise and phase displacement, the input with the amplitude of 120 mV or more is recommended.
When the noise causes disturbance in the output waveform (at a time of phase change) or HP output (Hall signal three-
phase synthesis output), insert a capacitor to the input to prevent such trouble. The Hall input is used as a signal to
determine the input to the restriction protection circuit and the protection circuit during reverse. Though noise is
ignored to a certain degree, due attention must be paid when using these protection circuits.
When all three phases of Hall input signal are entered, the output is turned OFF entirely (all of UL, VL, WL, UH, VH,
and WH OFF).
To enter the Hall IC output, fix one side of input (+ or –) to the voltage within the common-mode input range for Hall
device. This will allow input from 0 to V_CC1 for another single-side input.
8. Circuit for low-voltage protection
This circuit detects the voltage applied to the LVS pin. When this voltage drops below the operation voltage (see the
electric characteristics), the one-side output (UH, VH, and WH) is turned OFF. To prevent repetition of output
ON/OFF near the protection activation voltage, the hysteresis is provided. Accordingly, the output is not recovered
unless the voltage rises by about 0.5 V above the activation voltage.
The protection activation voltage is for the 5V system detection level. The detection level can be raised by connecting
the zenor diode in series to the LVS pin and by shifting the detection
level. The LVS pin inrush current at a time of detection is about 65 µA. ^{To detection power supply}
To stabilize rise of the zenor diode voltage, increase the diode current by
inserting the resistor between the LVS pin and GND.
When the protection circuit is not used, apply a voltage on a level where
To pin LVS
the protection is not activated, instead of setting the LVS pin open
(output OFF with the pin open).
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