Temperature detector in an integrated circuit
View Patent ↗A temperature detector in an integrated circuit comprises a temperature-dependent voltage generator, a ring oscillator, a timer and a clock-driven recorder. The temperature-dependent voltage generator is configured to generate at least one temperature-dependent voltage. The ring oscillator is configured to generate a clock signal, which is affected by one of the at least one temperature-dependent voltage. The timer is configured to generate a time-out signal, which is affected by one of the temperature-dependent voltage. The clock-driven recorder has a clock input terminal in response to the clock signal and time-out signal.
1. A temperature detector in an integrated circuit, comprising:
a temperature-dependent voltage generator configured to generate at least one temperature-dependent voltage;
a ring oscillator configured to generate a clock signal, wherein a clock rate of the clock signal is affected by one of the at least one temperature-dependent voltage;
a timer configured to generate a time-out signal, wherein the time-out signal is affected by one of the at least one temperature-dependent voltage; and
a clock-driven recorder having a clock input, wherein the clock input is in response to the clock signal and time-out signal, and the clock-driven recorder is used to estimate a temperature reading.
2. The temperature detector of claim 1 , wherein the clock-driven recorder is a shift register.
3. The temperature detector of claim 1 , wherein the clock-driven recorder is a counter.
4. The temperature detector of claim 1 , further comprising a look-up table for use in decoding the content of the clock-driven recorder.
5. The temperature detector of claim 1 , wherein the temperature-dependent voltage generator comprises only a bipolar transistor.
6. The temperature detector of claim 1 , wherein the temperature-dependent voltage generator comprises a bipolar transistor pair which includes two bipolar transistors having the same size with the collectors of the transistors coupled to the base thereof.
7. The temperature detector of claim 1 , wherein the ring oscillator has a voltage supply provided by one of the at least one temperature-dependent voltage.
8. The temperature detector of claim 1 , wherein the timer has PMOS and/or NMOS transistors which are controlled by one of the temperature-dependent voltage.
9. The temperature detector of claim 7 , wherein the temperature-dependent voltage is proportional to the ambient temperature.
10. The temperature detector of claim 1 , wherein the time-out signal appears later as the temperature increases.
11. A dynamic random access memory (DRAM) comprising:
a memory array having a plurality of memory cells;
a memory controller providing a refresh signal to maintain the content of the memory cells; and
a temperature detector according to claim 1 , wherein the temperature detector is used to determine the rate of the refresh signal.
12. The DRAM of claim 11 , wherein the clock-driven recorder is a shift register.
13. The DRAM of claim 11 , wherein the clock-driven recorder is a counter.
14. The DRAM of claim 11 , further comprising a look-up table for use in decoding the content of the clock-driven recorder.
15. The DRAM of claim 11 , wherein the ring oscillator has a voltage supply provided by one of the at least one temperature-dependent voltage.
16. The DRAM of claim 11 , wherein the timer has PMOS and/or NMOS transistors which are controlled by one of the temperature-dependent voltage.
17. The DRAM of claim 15 , wherein the temperature-dependent voltage is proportional to the ambient temperature.
18. The DRAM of claim 11 , wherein the time-out signal appears later as the temperature increases.