Low distortion level shifter
In one embodiment, a method includes: receiving, in a level shifter, an input signal from a first voltage domain that operates according to a first supply voltage; level shifting the input signal to at least one level-shifted signal having a second voltage greater than the first supply voltage; based on the at least one level-shifted signal, generating a first pulse signal and a second pulse signal; latching the first pulse signal through a latch circuit to form an output signal; and outputting the output signal to a second voltage domain, the second voltage domain to operate according to a second supply voltage greater than the first supply voltage.
1 . An apparatus comprising:
a level shifter to receive an input signal having a first voltage range and output at least one level-shifted signal based on the input signal, the level shifter comprising:
a first cross-coupled device pair to receive the input signal and an inverted input signal and to output a first gate control signal and a second gate control signal;
a first device coupled to the first cross-coupled device pair having a gate terminal driven by the first gate control signal;
a second device coupled to the first cross-coupled device pair having a gate terminal driven by the second gate control signal; and
a second cross-coupled device pair coupled to the first device and the second device, wherein the second cross-coupled device pair is to provide, to a pulse generation circuit, the at least one level-shifted signal comprising a first level-shifted signal and a second level-shifted signal, the second cross-coupled device pair comprising a pull-down circuit to define a first edge and a second edge of the at least one level-shifted signal;
the pulse generation circuit coupled to the level shifter, the pulse generation circuit to generate a first pulse and a second pulse based at least in part on the at least one level-shifted signal;
a latch circuit coupled to the pulse generation circuit, the latch circuit to receive the first pulse and the second pulse, and, based at least in part thereon, output a latched output signal; and
a shaper circuit to receive the latched output signal and shape a duty cycle of the latched output signal to output an output signal based on the latched output signal, the output signal having a second voltage range greater than the first voltage range.
2 . The apparatus of claim 1 , wherein the pulse generation circuit comprises delay circuitry to delay the at least one level-shifted signal.
3 . The apparatus of claim 2 , wherein the delay circuitry comprises:
a first inverter chain circuit to receive the first level-shifted signal and output a first delayed signal; and
a second inverter chain circuit to receive the second level-shifted signal and output a second delayed signal.
4 . The apparatus of claim 3 , wherein the delay circuitry further comprises:
a first logic circuit coupled to the first inverter chain circuit, the first logic circuit to receive the first level-shifted signal and the first delayed signal and based thereon, output the first pulse; and
a second logic circuit coupled to the second inverter chain circuit, the second logic circuit to receive the second level-shifted signal and the second delayed signal and output based thereon the second pulse.
5 . The apparatus of claim 4 , wherein the first pulse and the second pulse have a pulse width greater than a gate delay of the latch circuit.
6 . The apparatus of claim 1 , wherein the latch circuit comprises a set reset (SR) latch to receive the first pulse and the second pulse and output the latched output signal.
7 . The apparatus of claim 6 , wherein the shaper circuit comprises a plurality of inverters to receive the latched output signal and output the output signal based thereon.
8 . The apparatus of claim 1 , further comprising:
a digital domain comprising at least one circuit to generate the input signal, the digital domain to operate at the first voltage range; and
an input/output circuit coupled to the shaper circuit to communicate the output signal via a bus, the input/output circuit to operate at the second voltage range.
9 . The apparatus of claim 1 , wherein the apparatus comprises a low distortion level shifter.
10 . An apparatus comprising:
a level shifter to receive an input signal having a first voltage range and output at least one level-shifted signal based on the input signal, the level shifter comprising:
a first cross-coupled device pair to receive the input signal and an inverted input signal and to output a first gate control signal and a second gate control signal;
a first device coupled to the first cross-coupled device pair having a gate terminal driven by the first gate control signal;
a second device coupled to the first cross-coupled device pair having a gate terminal driven by the second gate control signal; and
a second cross-coupled device pair coupled to the first device and the second device, wherein the second cross-coupled device pair is to provide, to a pulse generation circuit, the at least one level-shifted signal comprising a first level-shifted signal and a second level-shifted signal;
the pulse generation circuit coupled to the level shifter, the pulse generation circuit to generate a first pulse and a second pulse based at least in part on the at least one level-shifted signal;
a latch circuit coupled to the pulse generation circuit, the latch circuit to receive the first pulse and the second pulse, and, based at least in part thereon, output a latched output signal, the latch circuit comprising:
a first logic circuit to receive the first pulse, a second latched output signal portion, and a first reset input signal, and output based thereon a first latched output signal; and
a second logic circuit to receive the second pulse, the first latched output signal and a second reset input signal, and output based thereon the second latched output signal; and
a shaper circuit to receive the latched output signal and output an output signal based on the latched output signal, the output signal having a second voltage range greater than the first voltage range.
11 . The apparatus of claim 10 , wherein the second cross-coupled device pair comprises a pull-down circuit to define a first edge and a second edge of the output signal.
12 . The apparatus of claim 10 , wherein the shaper circuit is to shape a duty cycle of the latched output signal.
13 . The apparatus of claim 10 , wherein the first reset input signal is to set the latch circuit to an initial condition.