Motor drive overcurrent detecting circuit, motor driving circuit without headroom voltage loss, and method for detecting overcurrent in motor driving circuit

A motor driving circuit without a headroom voltage loss comprising:

• a motor driving unit switched according to a driving control signal to drive a motor while including a source switching element group connected to an upper side of an H-bridge to apply a power voltage to the motor and a sink switching element group connected to a lower side of the H-bridge to sink a current flowing through the motor to a ground terminal;
• a driving control unit for applying the driving control signals for controlling the source and sink switching element groups of the motor driving unit;
• a sensing unit including a distribution switching element connected in parallel with each sink switching element of the sink switching element group and a sensing resistor connected in series with the distribution switching element, distributes a sensing current from the current flowing through the motor according to turn-on of the distribution switching element and senses the distributed current through the sensing resistor;
• and
• an on-resistance maintaining unit for maintaining on-resistance of the turned-on distribution switching element by turning on the distribution switching element connected in parallel with the turned-on sink switching element of the sink switching element group.

A method for detecting an overcurrent in a motor driving circuit comprising a source switching element group connected to an upper side of an H-bridge to apply a power voltage to a motor and a sink switching element group connected to a lower side of the H-bridge to sink a current flowing through the motor to a ground terminal, comprising:

• driving the motor by turning on one switching element of each of the source and sink switching element groups according to a driving control signal;
• maintaining on-resistance of the turned-on distribution switching element by turning on the distribution switching element connected in parallel with the turned-on sink switching element of the sink switching element group and distributing a sensing current from the current flowing through the motor according to the turn-on of the distribution switching element;
• and
• detecting an overcurrent by sensing the distributed current through a sensing resistor connected in series with the distribution switching element.