Output driving circuit, clock chip, and electronic device

1 . An output driving circuit, including a low-voltage push-pull module, an impedance calibration module, and an output isolation module,

wherein the low-voltage push-pull module is connected to a low-voltage bias voltage and is configured to receive and process a high-speed input signal, and to output an intermediate signal having a target level, wherein the low-voltage push-pull module includes one or more push-pull units, each including a low-voltage transistor pair including a first low-voltage transistor,

wherein the output isolation module is connected between an output terminal of the low-voltage push-pull module and an output terminal of the output driving circuit, and includes output isolation units each including a first high-voltage transistor, wherein the output isolation module is configured to be turned on when the output driving circuit works normally, and to output the intermediate signal as a target output signal of the output driving circuit,

wherein the impedance calibration module is configured to calibrate an output impedance of the output driving circuit, so that the output impedance of the output driving circuit is substantially constant; the impedance calibration module includes: a reference voltage generating circuit configured to generate a reference voltage; a calibration voltage generating circuit configured to generate a calibration voltage negatively correlated with the output impedance; and an impedance calibration circuit configured to adjust a control voltage according to the reference voltage and the calibration voltage;

wherein the calibration voltage generating circuit includes a third low-voltage transistor, a second high-voltage transistor, and a third resistor connected in series between the low-voltage bias voltage and ground; a connection point between the second high-voltage transistor and the third resistor outputs the calibration voltage, and the second high-voltage transistor receives the control voltage output by the impedance calibration circuit,

wherein the third low-voltage transistor and the first low-voltage transistor are of the same type, the second high-voltage transistor and the first high-voltage transistor are of the same type, an overall size of the third low-voltage transistor and the second high-voltage transistor is 1/N of that of the first low-voltage transistor and the first high-voltage transistor, and a ratio of a resistance of the third resistor to N is a target output impedance of the output driving circuit.

2 . The output driving circuit according to claim 1 , wherein the low-voltage push-pull module includes two push-pull units, and the two push-pull units receive a pair of differential signals.

3 . The output driving circuit according to claim 1 , wherein each of the push-pull units includes the first low-voltage transistor and a second low-voltage transistor with opposite polarities, and the first low-voltage transistor and the second low-voltage transistor are connected in series between the low-voltage bias voltage and ground.

4 . The output driving circuit according to claim 3 , wherein the first low-voltage transistor is a low-voltage PMOS transistor, and the second low-voltage transistor is a low-voltage NMOS transistor.

5 . The output driving circuit according to claim 4 , wherein a source of the first low-voltage transistor is connected to the low-voltage bias voltage, a drain of the first low-voltage transistor is connected to a drain of the second low-voltage transistor, a source of the second low-voltage transistor is connected to ground, a gate of the first low-voltage transistor is connected to a gate of the second low-voltage transistor, a connection point between the gate of the first low-voltage transistor and the gate of the second low-voltage transistor is configured as an input terminal of the corresponding push-pull unit, and a connection point between the drain of the first low-voltage transistor and the drain of the second low-voltage transistor is configured as the output terminal of the corresponding push-pull unit.

6 . The output driving circuit according to claim 3 , wherein the output isolation units are in one-to-one correspondence with the one or more push-pull units, wherein:

a drain of the first high-voltage transistor is connected to an output terminal of a corresponding push-pull unit and is configured to receive the intermediate signal;

a gate of the first high-voltage transistor receives the control voltage, wherein the control voltage turns on or off the first high-voltage transistor;

a source of the first high-voltage transistor is connected to the output terminal of the output driving circuit, wherein the intermediate signal is output as the target output signal via the output terminal of the output driving circuit when the first high-voltage transistor is turned on.

7 . The output driving circuit according to claim 6 , wherein the first high-voltage transistor is a native NMOS transistor.

8 . The output driving circuit according to claim 1 , wherein the reference voltage generating circuit includes a first resistor and a second resistor, the first resistor and the second resistor are connected in series between the low-voltage bias voltage and ground, and a connection point between the first resistor and the second resistor is configured as an output terminal of the reference voltage generating circuit to output the reference voltage.

9 . The output driving circuit according to claim 8 , wherein the first resistor and the second resistor have substantially the same resistance.

10 . The output driving circuit according to claim 1 , wherein the third low-voltage transistor is a low-voltage PMOS transistor, and the second high-voltage transistor is a high-voltage native NMOS transistor.

11 . The output driving circuit according to claim 10 , wherein a source of the third low-voltage transistor is connected to the low-voltage bias voltage, a drain of the third low-voltage transistor is connected to a drain of the second high-voltage transistor, a gate of the third low-voltage transistor is connected to ground, a source of the second high-voltage transistor is connected to a first end of the third resistor, a second end of the third resistor is connected to ground, a gate of the second high-voltage transistor receives the control voltage output by the impedance calibration circuit, and a connection point between the source of the second high-voltage transistor and the first end of the third resistor is configured as an output terminal of the calibration voltage generating circuit to output the calibration voltage.

12 . The output driving circuit according to claim 1 , wherein the impedance calibration circuit includes an operational amplifier, a positive input terminal of the operational amplifier is configured to receive the reference voltage, a negative input terminal of the operational amplifier is configured to receive the calibration voltage, and the operational amplifier outputs the control voltage based on the reference voltage and the calibration voltage.

13 . The output driving circuit according to claim 1 , wherein the output driving circuit further includes a voltage regulator, and the voltage regulator is configured to buck a power supply voltage to output the low-voltage bias voltage.

14 . The output driving circuit according to claim 1 , wherein the output driving circuit further includes one or more pre-driving modules, and each of the pre-driving modules is connected to a corresponding input terminal of the low-voltage push-pull module to pre-drive the high-speed input signal, wherein a working voltage of the pre-driving module is the low-voltage bias voltage.

15 . The output driving circuit according to claim 1 , wherein the low-voltage bias voltage is about 0.75 V.

16 . A clock chip, including:

a clock signal generating circuit, configured to generate a high-speed clock signal; and

an output driving circuit, including a low-voltage push-pull module, an impedance calibration module, and an output isolation module, wherein the output driving circuit is configured to input the high-speed clock signal and output a target high-speed clock signal,

wherein the low-voltage push-pull module is connected to a low-voltage bias voltage and is configured to receive and process the high-speed clock signal, and to output an intermediate signal having a target level, wherein the low-voltage push-pull module includes one or more push-pull units, each including a low-voltage transistor pair including a first low-voltage transistor,

wherein the output isolation module is connected between an output terminal of the low-voltage push-pull module and an output terminal of the output driving circuit, and includes output isolation units each including a first high-voltage transistor, wherein the output isolation module is configured to be turned on when the output driving circuit works normally, and to output the intermediate signal as the target high-speed clock signal,

wherein the impedance calibration module is configured to calibrate an output impedance of the output driving circuit, so that the output impedance of the output driving circuit is substantially constant; the impedance calibration module includes: a reference voltage generating circuit configured to generate a reference voltage; a calibration voltage generating circuit configured to generate a calibration voltage negatively correlated with the output impedance; and an impedance calibration circuit configured to adjust a control voltage according to the reference voltage and the calibration voltage;

wherein the calibration voltage generating circuit includes a third low-voltage transistor, a second high-voltage transistor, and a third resistor connected in series between the low-voltage bias voltage and ground; a connection point between the second high-voltage transistor and the third resistor outputs the calibration voltage, and the second high-voltage transistor receives the control voltage output by the impedance calibration circuit,

wherein the third low-voltage transistor and the first low-voltage transistor are of the same type, the second high-voltage transistor and the first high-voltage transistor are of the same type, an overall size of the third low-voltage transistor and the second high-voltage transistor is 1/N of that of the first low-voltage transistor and the first high-voltage transistor, and a ratio of a resistance of the third resistor to N is a target output impedance of the output driving circuit.

17 . An electronic device, including:

a signal generating circuit, configured to generate a high-speed signal; and

an output driving circuit, including a low-voltage push-pull module, an impedance calibration module, and an output isolation module, wherein the output driving circuit is configured to input the high-speed signal and output a target high-speed signal,

wherein the low-voltage push-pull module is connected to a low-voltage bias voltage and is configured to receive and process the high-speed signal, and to output an intermediate signal having a target level, wherein the low-voltage push-pull module includes one or more push-pull units, each including a low-voltage transistor pair including a first low-voltage transistor,

wherein the output isolation module is connected between an output terminal of the low-voltage push-pull module and an output terminal of the output driving circuit, and includes output isolation units each including a first high-voltage transistor, wherein the output isolation module is configured to be turned on when the output driving circuit works normally, and to output the intermediate signal as the target high-speed signal,

wherein the impedance calibration module is configured to calibrate an output impedance of the output driving circuit, so that the output impedance of the output driving circuit is substantially constant; the impedance calibration module includes: a reference voltage generating circuit configured to generate a reference voltage; a calibration voltage generating circuit configured to generate a calibration voltage negatively correlated with the output impedance; and an impedance calibration circuit configured to adjust a control voltage according to the reference voltage and the calibration voltage;

wherein the calibration voltage generating circuit includes a third low-voltage transistor, a second high-voltage transistor, and a third resistor connected in series between the low-voltage bias voltage and ground; a connection point between the second high-voltage transistor and the third resistor outputs the calibration voltage, and the second high-voltage transistor receives the control voltage output by the impedance calibration circuit,

wherein the third low-voltage transistor and the first low-voltage transistor are of the same type, the second high-voltage transistor and the first high-voltage transistor are of the same type, an overall size of the third low-voltage transistor and the second high-voltage transistor is 1/N of that of the first low-voltage transistor and the first high-voltage transistor, and a ratio of a resistance of the third resistor to N is a target output impedance of the output driving circuit.