METHOD AND APPARATUS FOR DETECTING REVERSE CURRENT, AND METHOD AND APPARATUS FOR DRIVING MOTOR
First Claim
1. A method for detecting a reverse flow of a phase current supplied to a motor coil from a node between a higher power supply-side transistor and a lower power supply-side transistor, which are connected in series with each other to form a half bridge, by driving the half bridge under a PWM control, the method comprising the steps of:
- determining whether an electrical conduction control to the motor coil is in a predetermined state based on a timing signal representing a timing at which to conduct a source current or a sink current through the motor coil and a control signal for the half bridge;
comparing a voltage at the node with a threshold value;
determining whether the voltage at the node is shifted from an ideal value in the predetermined state based on a result of the comparison; and
determining that the phase current is reversed if it is determined that the electrical conduction control to the motor coil is in the predetermined state and if it is determined that the voltage at the node is shifted from the ideal value.
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Accused Products
Abstract
A reverse current detection apparatus determines whether an electrical conduction control to a motor coil of a motor is in a predetermined state based on a timing signal representing a timing at which to conduct a source current or a sink current through the motor coil and a control signal for a half bridge in a power stage, and compares the output voltage of the power stage with a threshold value, so as to detect the presence/absence of a reverse flow of a phase current based on these results. A motor driving apparatus for driving a motor under a PWM control includes a rectification switching section for switching a rectification scheme from one to another based on the reverse current detection apparatus and a detection result thereof.
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Citations
21 Claims
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1. A method for detecting a reverse flow of a phase current supplied to a motor coil from a node between a higher power supply-side transistor and a lower power supply-side transistor, which are connected in series with each other to form a half bridge, by driving the half bridge under a PWM control, the method comprising the steps of:
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determining whether an electrical conduction control to the motor coil is in a predetermined state based on a timing signal representing a timing at which to conduct a source current or a sink current through the motor coil and a control signal for the half bridge; comparing a voltage at the node with a threshold value; determining whether the voltage at the node is shifted from an ideal value in the predetermined state based on a result of the comparison; and determining that the phase current is reversed if it is determined that the electrical conduction control to the motor coil is in the predetermined state and if it is determined that the voltage at the node is shifted from the ideal value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for detecting a reverse flow of a phase current supplied to a motor coil from a node between a higher power supply-side transistor and a lower power supply-side transistor, which are connected in series with each other to form a half bridge, by driving the half bridge under a PWM control, the apparatus comprising:
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a state determination section for receiving a timing signal representing a timing at which to conduct a source current or a sink current through the motor coil and a control signal for the half bridge, and for determining whether an electrical conduction control to the motor coil is in a predetermined state based on the received signals; a comparator for comparing a voltage at the node with a threshold value; and a reverse current determination section for determining whether the phase current is reversed based on a determination result of the state determination section and a comparison result of the comparator. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification