Transmission device
A transmission device is provided. The transmission device includes a voltage generator, a convertor, a voltage buffer and a transmission element. The voltage generator generates a first voltage signal according to a first current. The convertor generates a second current using a source current proportional to a temperature, generates a third current according to the first voltage signal, and converts a sum of the second current and the third current to a second voltage signal. The voltage buffer generates a driving voltage proportional to the temperature according to the second voltage signal. The transmission element operates based on the driving voltage.
1. A transmission device, comprising:
a voltage generator, configured to generate a first voltage signal according to a first current;
a convertor, coupled to the voltage generator, configured to generate a second current using a source current proportional to a temperature, generate a third current according to the first voltage signal, and convert a sum of the second current and the third current to a second voltage signal;
a voltage buffer, coupled to the convertor, configured to generate a driving voltage according to the second voltage signal; and
a transmission element, coupled to the voltage buffer, configured to operate based on the driving voltage,
wherein the driving voltage is proportional to the temperature.
2. The transmission device of claim 1 , wherein the third current is proportional to the first current and lower than the first current.
3. The transmission device of claim 1 , wherein when the temperature is a default temperature, the sum of the second current and the third current is equal to the first current.
4. The transmission device of claim 3 , wherein:
when the temperature is high than the default temperature, the sum of the second current and the third current is high than the first current, and
when the temperature is low than the default temperature, the sum of the second current and the third current is low than the first current.
5. The transmission device of claim 1 , wherein the voltage generator comprises:
an operational amplifier, wherein a first input terminal of the operational amplifier receives a reference voltage, wherein an output terminal of the operational amplifier outputs the first voltage signal;
a first resistor, coupled between a second input terminal of the operational amplifier and a reference low voltage; and
a first transistor, wherein a first terminal of the first transistor is coupled to a reference high voltage, wherein a second terminal of the first transistor is coupled to the second input terminal of the operational amplifier, wherein a control terminal of the first transistor is coupled to the output terminal of the operational amplifier.
6. The transmission device of claim 5 , wherein the voltage generator generates a feedback voltage according to a resistance value of the first resistor and a current value of the first current flowing through the first resistor, and generates the first voltage signal according to the reference voltage and the feedback voltage.
7. The transmission device of claim 5 , wherein the convertor comprises:
a current source, coupled to a first node, configured to provide the source current;
a second resistor, coupled between a second node and the reference low voltage;
a current mirror, coupled to the first node and the second node, configured to mirror the source current to generate the second current flowing through the second node; and
a second transistor, wherein a first terminal of the second transistor is coupled to the reference high voltage, wherein a second terminal of the second transistor is coupled to the second node, wherein a control terminal of the second transistor is coupled to the output terminal of the operational amplifier, wherein the control terminal of the second transistor receives the first voltage signal.
8. The transmission device of claim 7 , wherein the convertor generates the second voltage signal according to a resistance value of the second resistor and a current value of the sum of the second current and the third current.
9. The transmission device of claim 7 , wherein the current mirror comprises:
a third transistor, wherein a first terminal of the third transistor is coupled to the reference high voltage;
a fourth transistor, wherein a first terminal of the fourth transistor is coupled to a second terminal of the third transistor and a control terminal of the third transistor, wherein a second terminal of the fourth transistor and a control terminal of the fourth transistor are coupled to the first node;
a fifth transistor, wherein a first terminal of the fifth transistor is coupled to the reference high voltage, wherein a control terminal of the fifth transistor is coupled to the control terminal of the third transistor; and
a sixth transistor, wherein a first terminal of the sixth transistor is coupled to a second terminal of the fifth transistor, wherein a second terminal of the sixth transistor is coupled to the second node, wherein a control terminal of the sixth transistor is coupled to the control terminal of the fourth transistor.
10. The transmission device of claim 5 , wherein the convertor comprises:
a current source, configured to provide the source current;
a first current mirror, coupled to a first node and the current source, configured to mirror the source current to generate a fourth current flowing through the first node;
a second resistor, coupled between a second node and the reference low voltage;
a second current mirror, coupled to the first node and the second node, configured to mirror the fourth current to generate the second current flowing through the second node; and
a second transistor, wherein a first terminal of the second transistor is coupled to the reference high voltage, wherein a second terminal of the second transistor is coupled to the second node, wherein a control terminal of the second transistor is coupled to the output terminal of the operational amplifier, wherein the control terminal of the second transistor receives the first voltage signal.