Induction type power supply system and intruding metal detection method thereof

1. A method used for an induction type power supply system, for detecting whether an intruding metal exists in a power transmission region of the induction type power supply system, the method comprising:

interrupting at least one driving signal of the induction type power supply system to stop driving a supplying-end coil of the induction type power supply system;

detecting an attenuation status of a coil signal on the supplying-end coil when driving of the supplying-end coil is interrupted; and

determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal;

wherein the step of determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal comprises:

configuring a threshold voltage;

calculating a number of peaks reaching the threshold voltage in the coil signal after the at least one driving signal is interrupted; and

determining that the intruding metal exists in the power transmission region of the induction type power supply system when the number is smaller than a threshold value.

2. The method of claim 1 , wherein the step of determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal comprises:

determining that the intruding metal exists in the power transmission region of the induction type power supply system when an attenuation speed of the coil signal is greater than a threshold value.

3. The method of claim 1 , wherein the step of calculating the number of peaks reaching the threshold voltage in the coil signal after the at least one driving signal is interrupted comprises:

enabling a counter when the at least one driving signal is interrupted;

detecting whether a peak of the coil signal reaches the threshold voltage during an oscillation cycle of the coil signal after enabling the counter;

increasing the counter by one when detecting that the peak of the coil signal reaches the threshold voltage, and then detecting whether another peak of the coil signal reaches the threshold voltage during a next oscillation cycle of the coil signal; and

obtaining a counting result of the counter as the number of peaks reaching the threshold voltage in the coil signal when detecting that there is a peak of the coil signal failing to reach the threshold voltage.

4. A method used for an induction type power supply system, for detecting whether an intruding metal exists in a power transmission region of the induction type power supply system, the method comprising:

interrupting at least one driving signal of the induction type power supply system to stop driving a supplying-end coil of the induction type power supply system;

detecting an attenuation status of a coil signal on the supplying-end coil when driving of the supplying-end coil is interrupted; and

determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal,

wherein the step of determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal comprises:

configuring a threshold voltage;

measuring an attenuation period of the coil signal after the at least one driving signal is interrupted, wherein the attenuation period starts when the at least one driving signal is interrupted and ends when there appears a peak of the coil signal failing to reach the threshold voltage; and

determining that the intruding metal exists in the power transmission region of the induction type power supply system when the attenuation period is shorter than a threshold value.

5. The method of claim 4 , wherein the step of measuring the attenuation period of the coil signal after the at least one driving signal is interrupted comprises:

enabling a timer when the at least one driving signal is interrupted;

detecting whether a peak of the coil signal reaches the threshold voltage during an oscillation cycle of the coil signal after enabling the timer;

after detecting that the peak of the coil signal reaches the threshold voltage, detecting whether another peak of the coil signal reaches the threshold voltage during a next oscillation cycle of the coil signal; and

stopping the timer and obtaining a timing result of the timer as the attenuation period of the coil signal when detecting that there is a peak of the coil signal failing to reach the threshold voltage.

6. A method used for an induction type power supply system, for detecting whether an intruding metal exists in a power transmission region of the induction type power supply system, the method comprising:

interrupting at least one driving signal of the induction type power supply system to stop driving a supplying-end coil of the induction type power supply system;

detecting an attenuation status of a coil signal on the supplying-end coil when driving of the supplying-end coil is interrupted; and

determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal,

wherein the step of determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal comprises:

configuring a plurality of threshold voltages;

obtaining an attenuation pattern of the coil signal according to attenuation periods of peaks of the coil signal respectively attenuating to the plurality of threshold voltages; and

determining whether the intruding metal exists in the power transmission region of the induction type power supply system and determining a type or size of the intruding metal according to the attenuation pattern.

7. A method used for an induction type power supply system, for detecting whether an intruding metal exists in a power transmission region of the induction type power supply system, the method comprising:

interrupting at least one driving signal of the induction type power supply system to stop driving a supplying-end coil of the induction type power supply system;

detecting an attenuation status of a coil signal on the supplying-end coil when driving of the supplying-end coil is interrupted;

determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal; and

starting the at least one driving signal in a phase-shift manner after determining whether the intruding metal exists in the power transmission region of the induction type power supply system;

wherein the step of starting the at least one driving signal in the phase-shift manner comprises:

starting the at least one driving signal wherein a phase of a first driving signal and a phase of a second driving signal among the at least one driving signal are the same; and

gradually adjusting one or both of the phases of the first driving signal and the second driving signal, until the phase of the first driving signal and the phase of the second driving signal are opposite.

8. A method used for an induction type power supply system, for detecting whether an intruding metal exists in a power transmission region of the induction type power supply system, the method comprising:

interrupting at least one driving signal of the induction type power supply system to stop driving a supplying-end coil of the induction type power supply system;

detecting an attenuation status of a coil signal on the supplying-end coil when driving of the supplying-end coil is interrupted;

determining whether the intruding metal exists in the power transmission region of the induction type power supply system according to the attenuation status of the coil signal; and

detecting a peak voltage of the coil signal and configuring at least one threshold voltage according to the peak voltage, wherein the at least one threshold voltage is used for determining whether the intruding metal exists in the power transmission region of the induction type power supply system;

wherein the at least one threshold voltage is smaller than the peak voltage.