Oscillating circuit and electronic device

An oscillating circuit, comprising:

• a capacitor charging and discharging circuit unit, a voltage comparison circuit unit, and a threshold voltage generation circuit unit;
• wherein the capacitor charging and discharging circuit unit comprises a variable current source, negative current mirrors, positive current mirrors, a first switching transistor, a second switching transistor, and a capacitor, wherein the variable current source provides a variable current, the capacitor is grounded at one end and connected to a first node at the other end;
• the negative current mirrors and the first switching transistor mirror the variable current to the first node to charge the capacitor;
• the positive current mirrors and the second switching transistor mirror the variable current to the first node to discharge the capacitor;
• a control terminal of the first switching transistor and a control terminal of the second switching transistor are coupled, and the control terminal of the first switching transistor and the control terminal of the second switching transistor are connected to a second node;
• wherein the voltage comparison circuit unit compares and amplifies a voltage difference between a third node and the first node and converts it into a single-ended signal;
• the single-ended signal is connected to the threshold voltage generation circuit unit, and regulates and controls an output voltage at an output of the threshold voltage generation circuit unit, the output of the threshold voltage generation circuit unit being connected to the third node;
• the single-ended signal is inverted and connected to the second node;
• one of the first switching transistor and the second switching transistor is cyclically and alternately turned on, causing the capacitor to be periodically charged and discharged, resulting a sawtooth wave voltage at the first node.