Circuit, method and system for automatic level switching

A method for automatic level switching, applied to a circuit for automatic level switching, wherein the circuit for automatic level switching, comprising:

• a level selector, a chip IO interface and a level detector,
• the level selector is configured with n input terminals each connected to different input voltages, and an output terminal of the level selector provides the chip IO interface with an interface level;
• the chip IO interface is connected to an off-chip device, wherein n is a positive integer greater than or equal to 2;
• and
• a control terminal of the level detector is connected to a control terminal of the level selector, and a detection terminal of the level detector is connected to the chip IO interface, the level detector is configured to detect a voltage at the chip IO interface, obtain an operating voltage value of the off-chip device based on the detected voltage at the chip IO interface, generate a control signal based on the operating voltage value, and control, via the control signal, the level selector to switch a corresponding input terminal to provide the chip IO interface with a chip IO interface level consistent with the operating voltage of the off-chip device;
• wherein the method comprises:
• upon the off-chip device is powered on:
• controlling the level selector to select one of the n input terminals which is connected to a maximum input voltage, to provide the chip IO interface with the interface level equal to the maximum input voltage;
• in response to the off-chip device being in an operating state after being powered on:
• detecting, by the level detector, the voltage at the chip IO interface;
• obtaining, by the level detector, the operating voltage value of an off-chip device based on the detected voltage at the chip IO interface;
• generating, by the level detector, the control signal based on the operating voltage value;
• sending, by the level detector, the control signal to the level selector;
• and
• switching, by the level selector, the input terminal to provide the chip IO interface with the chip IO interface level consistent with the operating voltage of the off-chip device, based on the control signal.

A system for automatic level switching, comprising:

• a circuit for automatic level switching, wherein the circuit for automatic level switching comprising:
• a level selector, a chip IO interface and a level detector, wherein:
• the level selector is configured with n input terminals each connected to different input voltages, and an output terminal of the level selector provides the chip IO interface with an interface level;
• the chip IO interface is connected to an off-chip device, wherein n is a positive integer greater than or equal to 2;
• a control terminal of the level detector is connected to a control terminal of the level selector, and a detection terminal of the level detector is connected to the chip IO interface, the level detector is configured to detect a voltage at the chip IO interface, obtain an operating voltage value of the off-chip device based on the detected voltage at the chip IO interface, generate a control signal based on the operating voltage value, and control, via the control signal, the level selector to switch a corresponding input terminal to provide the chip IO interface with a chip IO interface level consistent with the operating voltage of the off-chip device;
• and
• upon the off-chip device is powered on, the level selector is configured to select one of the n input terminals which is connected to a maximum input voltage to provide the chip IO interface with an interface level equal to the maximum input voltage;
• and
• the off-chip device, connected to the chip IO interface in the circuit for automatic level switching, the circuit for automatic level switching is configured to identify the operating voltage of the off-chip device, and enable the chip IO interface level to be consistent with the operating voltage of the off-chip device through level switching.