Voltage translator using low voltage power supply
A voltage translation device is disclosed. The voltage translation device includes an input circuit, operating in a first voltage domain, that is configured to receive an input signal. The voltage translation device also includes an output circuit, operating in a second voltage domain, that includes a latch circuit. The voltage translation device also includes a driver circuit that is controlled by the input circuit to pass a voltage from the first voltage domain to the latch circuit in order to trigger the latch circuit to output an output signal in the second voltage domain according to the input signal in the first voltage domain.
1. An apparatus, comprising:
an input circuit, operating in a first voltage domain, configured to receive an input signal;
an output circuit, operating in a second voltage domain, and including a latch circuit, the first voltage domain and the second voltage domain each spanning a voltage range less than a translation voltage separating the first voltage domain and the second voltage domain; and
a driver circuit controlled by the input circuit to pass a voltage from the first voltage domain to the latch circuit, the passed voltage triggers the latch circuit to output an output signal in the second voltage domain according to the input signal in the first voltage domain.
2. The apparatus according to claim 1 , wherein:
the first voltage domain includes voltages spanning a lower rail voltage of the first voltage domain and an upper rail voltage of the first voltage domain; and
the second voltage domain includes voltages spanning a lower rail voltage of the second voltage domain and an upper rail voltage of the second voltage domain.
3. The apparatus according to claim 2 , wherein the difference between the upper rail voltage of the first voltage domain and the lower rail voltage of the first voltage domain is less than 2 volts.
4. The apparatus according to claim 2 , wherein the difference between the upper rail voltage of the second voltage domain and the lower rail voltage of the second voltage domain is less than 2 volts.
5. The apparatus according to claim 2 , wherein the lower rail voltage of the first voltage domain and the upper rail voltage of the first voltage domain are lower than the lower rail voltage of the second voltage domain and the upper rail voltage of the second voltage domain.
6. The apparatus according to claim 5 , wherein the passed voltage is the lower rail voltage of the first voltage domain.
7. The apparatus according to claim 2 , wherein the lower rail voltage of the first voltage domain and the upper rail voltage of the first voltage domain are higher than the lower rail voltage of the second voltage domain and the upper rail voltage of the second voltage domain.
8. The apparatus according to claim 7 , wherein the passed voltage is the upper rail voltage of the first voltage domain.
9. The apparatus according to claim 1 , wherein the input circuit includes:
a first input switch that is turned ON when the input signal is a high voltage in the first voltage domain and turned OFF when the input signal is low voltage in the first voltage domain; and
a second input circuit switch that is turned ON when the input signal is the low voltage in the first voltage domain and turned OFF when the input signal is the high voltage in the first voltage domain.
10. The apparatus according to claim 9 , wherein the latch circuit includes:
a set-latch switch, wherein the output signal of the latch circuit is a high voltage in the second voltage domain when the set set-latch switch is turned ON; and
a reset-latch switch, wherein the output signal of the latch circuit is a low voltage in the second voltage domain when the reset-latch switch is turned ON.
11. The apparatus according to claim 10 , wherein the driver circuit includes:
a first pass gate connected between first input switch and the set-latch switch that passes the voltage from the first voltage domain to turn ON the set-latch switch when the first input switch is turned ON; and
a second pass gate connected between the second input switch and the reset-latch switch that passes the voltage from the first voltage domain to turn ON the reset-latch switch when the second switch is turned ON.
12. A method, comprising:
receiving an input signal at an input circuit operating in a first voltage domain;
controlling, based on the input signal, a driver circuit to pass a voltage from the first voltage domain to an output circuit operating in a second voltage domain, the first voltage domain and the second voltage domain each spanning a voltage range less than a translation voltage separating the first voltage domain and the second voltage domain; and
configuring, based on the passed voltage, a latch circuit in the output circuit, to output an output signal in the second voltage domain according to the input signal in the first voltage domain.
13. The method according to claim 12 , wherein:
the first voltage domain includes voltages spanning a lower rail voltage of the first voltage domain and an upper rail voltage of the first voltage domain; and wherein
the second voltage domain includes voltages spanning a lower rail voltage of the second voltage domain and an upper rail voltage of the second voltage domain.
14. The method according to claim 13 , wherein:
the difference between the upper rail voltage of the first voltage domain and the lower rail voltage of the first voltage domain is less than 2 volts, and
the difference between the upper rail voltage of the second voltage domain and the lower rail voltage of the second voltage domain is less than 2 volts.
15. The method according to claim 13 , wherein the controlling, based on the input signal, a driver circuit includes:
turning ON a first input circuit switch in the input circuit to connect a first pass gate in the driver circuit to the voltage in the first voltage domain when the input signal is a high voltage in the first voltage domain; and
turning ON a second input circuit switch in the input circuit to connect a second pass gate in the driver circuit to the voltage in the first voltage domain when the input signal is a low voltage in the first voltage domain.
16. The method according to claim 15 , wherein the upper rail voltage of the first voltage domain and the lower rail voltage of the first voltage domain are lower than the upper rail voltage of the second voltage domain and the lower rail voltage of the second voltage domain.
17. The method according to claim 15 , wherein the upper rail voltage of the first voltage domain and the lower rail voltage of the first voltage domain are higher than the upper rail voltage of the second voltage domain and the lower rail voltage of the second voltage domain.
18. The method according to claim 15 , wherein the configuring, based on the passed voltage, a latch circuit in the output circuit includes:
passing, via a first pass gate connected between the first input circuit switch and a set-latch switch of the latch circuit, the voltage from the first voltage domain to turn ON the set-latch switch, wherein the output signal of the latch circuit is a high voltage in the second voltage domain when the set set-latch switch is turned ON; and
passing, via a second pass gate connected between the second input circuit switch and a reset-latch switch of the latch circuit, the voltage from the first voltage domain to turn ON the reset-latch switch, wherein the output signal of the latch circuit is a low voltage in the second voltage domain when the reset set-latch switch is turned ON.
19. A system for voltage translation, the system comprising:
an input circuit operating in a first voltage domain that is configured to receive an input signal;
a latch circuit operating in a second voltage domain, the first voltage domain and the second voltage domain each spanning a voltage range less than a translation voltage separating the first voltage domain and the second voltage domain; and
a first pass gate and a second pass gate each being connected between the input circuit and the latch circuit, the first pass gate and the second pass gate being controlled by the input circuit to pass a voltage from the first voltage domain to set or reset the latch circuit to a voltage in the second voltage domain according to the input signal.
20. The system for voltage translation according to claim 19 , wherein the latch comprises:
a set-latch switch with a gate connected only to the first pass gate; and
a reset-latch switch with a gate connected only to the second pass gate.