Temperature compensated bias network
View Patent ↗A method and apparatus for a temperature compensated bias network, such as may be embodied as an integrated circuit is disclosed. Embodiments provide for a wide range of desired temperature characteristics with good stability. Current mirror components with active leakage circuits may act to provide consistent operating parameters over a wide range of temperatures. Improved compensation and linearity may be provided using features disclosed.
1. A circuit for providing a temperature compensated current comprising:
a input transistor having an input transistor control terminal and having an input transistor current terminal passing a reference current;
a first buffer transistor having a first buffer transistor control terminal operable to receive a buffer control voltage proportional to the reference current and further having a first buffer transistor current terminal operable to pass a first leakage current;
a first leakage block comprising a temperature dependent block operable to pass the first leakage current;
a second buffer transistor having a second buffer transistor control terminal operable to receive the buffer control voltage and further having a second buffer transistor current terminal operable to pass a second leakage current;
a second leakage block operable to pass the second leakage current; and
an output transistor operable to generate an output current proportional to the reference current and further proportional to a ratio of the first and second leakage currents.
2. The circuit of claim 1 wherein:
the second leakage block consists of an ohmic resistance.
3. The circuit of claim 1 wherein:
the second leakage block comprises a diode.
4. The circuit of claim 3 wherein:
the second leakage block further comprises an ohmic resistance.
5. The circuit of claim 1 wherein
the temperature dependent block comprises a current mirror and an offset linearizing resistor.
6. A circuit for providing a temperature compensated current comprising:
a input transistor having an input transistor control terminal and having an input transistor current terminal passing a reference current;
a first buffer transistor having a first buffer transistor control terminal operable to receive a buffer control voltage proportional to the reference current and further having a first buffer transistor current terminal operable to pass a first leakage current;
a first leakage block operable to pass the first leakage current;
a second buffer transistor having a second buffer transistor control terminal operable to receive the buffer control voltage and further having a second buffer transistor current terminal operable to pass a second leakage current;
a second leakage block comprising a temperature dependent block operable to pass the second leakage current; and
an output transistor operable to generate an output current proportional to the reference current and further proportional to a ratio of the first and second leakage currents.
7. The circuit of claim 6 wherein:
the first leakage block consists of an ohmic resistance.
8. The circuit of claim 6 wherein:
the first leakage block comprises a diode.
9. The circuit of claim 8 wherein:
the first leakage block further comprises an ohmic resistance.
10. The circuit of claim 6 wherein
the temperature dependent block comprises a current mirror and an offset linearizing resistor.
11. A method for providing a temperature compensated current comprising the acts of:
mirroring a proportion of a reference current using an input transistor having an input transistor control terminal passing a control current and further using an output transistor;
providing an input buffer transistor and an output buffer transistor;
ratioing a temperature dependent leakage current of the input buffer transistor with a leakage current of the output buffer transistor; and
generating an output current proportional to the reference current and further proportional to the ratioing
whereby the circuit operates to produce a current with temperature compensation.
12. A method for providing a temperature compensated current comprising the acts of:
mirroring a proportion of a reference current using an input transistor having an input transistor control terminal passing a control current and further using an output transistor;
providing an input buffer transistor and an output buffer transistor;
ratioing a leakage current of the input buffer transistor with a temperature dependent leakage current of the output buffer transistor; and
generating an output current proportional to the reference current and further proportional to the ratioing
whereby the circuit operates to produce a current with temperature compensation.