Low power output driver

• US 7,821,297 B2
• Filed: 10/31/2007
• Issued: 10/26/2010
• Est. Priority Date: 09/24/2004
• Status: Active Grant

• Current Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Original Assignee: Integrated Device Technology Incorporated (Renesas Electronics Corporation)
• Inventors: Isik, Tacettin, Clementi, Daniel M., Poitras, Louis F.
• Primary Examiner(s): Barnie; Rexford N
• Assistant Examiner(s): Crawford; Jason
• Application Number:
  US11/931,191
• Publication Number:
  US 20080048724A1
• Time in Patent Office: 1,091 Days
• Field of Search: 326/63, 326/68, 326 80- 83, 326 86- 87, 326/115, 327108-109, 327/333
• US Class Current: 326/86
• CPC Class Codes: H03K 19/018521 of complementary type, e.g. CMOS
• CPC Class Codes: H04L 25/0278 Arrangements for impedance matching

Abstract

A low power output driver includes one of a regulated reduced voltage source that receives a supply voltage and outputs a regulated reduced voltage that is a lower voltage than the supply voltage. The driver also includes a first driver input that receives a first logic signal, a second driver input that receives a second logic signal, a first driver output that outputs a first output signal and a second driver output that outputs a second output signal. The driver includes first, second, third and fourth n-type metal oxide semiconductor (NMOS) that are cross-connected between the reduced voltage and the first and second driver outputs or a constant voltage internal ground. When the second input is high, the second NMOS and the third NMOS are gated on, the second driver output is raised to the reduced voltage and the first driver output is pulled down to the constant voltage ground.

Claims

1. A low power output driver comprising:

(a) one of a series-regulated and a switching-mode-regulated reduced voltage source that receives a supply voltage and outputs a continuously regulated reduced voltage that is a lower voltage than the supply voltage;

(b) a first driver input that receives a first logic signal;

(c) a second driver input that receives a second logic signal;

(d) a first driver output that outputs a first output signal;

(e) a second driver output that outputs a second output signal;

(f) a first n-type metal oxide semiconductor (NMOS) having a gate, a source and a drain, the source and the drain of the first NMOS being electrically coupled between the reduced voltage V_L and the first driver output, the gate of the first NMOS being electrically coupled to the first driver input;

(g) a second NMOS having a gate, a source and a drain, the source and the drain of the second NMOS being electrically coupled between the first driver output and a constant voltage internal ground, the gate of the second NMOS being electrically coupled to the second driver input;

(h) a third NMOS having a gate, a source and a drain, the source and the drain of the third NMOS being electrically coupled between the reduced voltage V_L and the second driver output, the gate of the third NMOS being electrically coupled to the second driver input; and

(i) a fourth NMOS having a gate, a source and a drain, the source and the drain of the fourth NMOS being electrically coupled between the second driver output and the constant voltage internal ground, the gate of the fourth NMOS being electrically coupled to the first driver input,

when the first driver input is high and the second driver input is low, the first NMOS and the fourth NMOS are gated on, the first driver output is raised to the reduced voltage V_L, the second driver output is pulled down to the constant voltage internal ground, and current through the first NMOS and the fourth NMOS is reduced to zero,

when the second driver input is high and the first driver input is low, the second NMOS and the third NMOS are gated on, the second driver output is raised to the reduced voltage V_L, the first driver output is pulled down to the constant voltage internal ground, and current through the second NMOS and the third NMOS is reduced to zero, and

the constant voltage internal ground differentiates the driver output raised to the reduced voltage from the driver output pulled down to the constant voltage internal ground.

2. The low power output driver of claim 1, wherein the continuously regulated reduced voltage source includes:

(a1) a voltage source input that receives the supply voltage V_DD; and

(a2) a voltage source output that outputs the regulated reduced voltage V_L.

3. The low power output driver of claim 2, wherein the continuously regulated reduced voltage source further includes:

(a3) a voltage source MOS having a gate, a source and a drain, the source and the drain of the voltage source MOS being electrically coupled between the voltage source input and voltage source output; and

(a4) an operational amplifier having a non-inverting input, an inverting input and an amplifier output, the non-inverting input being electrically coupled to an internal reference, the inverting input being electrically coupled to the voltage source output and the amplifier output being electrically coupled to the gate of the voltage source MOS.

4. The low power output driver of claim 3, wherein the inverting input of the operational amplifier is capacitively coupled to the constant voltage internal ground.

5. The low power output driver of claim 3, wherein the internal reference includes one of a bandgap reference, a resistance voltage divider, an external reference and an external bandgap.

6. The low power output driver of claim 2, wherein the continuously regulated reduced voltage source further includes:

(a3) a voltage source bipolar transistor, the voltage source bipolar transistor being electrically coupled between the voltage source input and voltage source output; and

(a4) an operational amplifier having a non-inverting input, an inverting input and an amplifier output, the non-inverting input being electrically coupled to an internal reference, the inverting input being electrically coupled to the voltage source output and the amplifier output being electrically coupled to a gate of the voltage source bipolar transistor.

7. The low power output driver of claim 1, wherein the supply voltage is between about 1.0 and about 6.0 volts direct current (VDC) and the reduced voltage is between about 0.1 and about 1.5 VDC.

8. The low power output driver of claim 1, wherein the supply voltage is about 3.3 volts direct current (VDC) and the reduced voltage is about 0.75 VDC.

9. The low power output driver of claim 1, wherein the reduced voltage source and the first, second, third and fourth NMOS are disposed in a common integrated circuit (IC).

10. The low power output driver of claim 1, wherein the first, second, third and fourth NMOS are disposed in a common integrated circuit (IC) and the reduced voltage source is disposed external to the IC.

11. The low power output driver of claim 1, wherein the first and second driver outputs form a voltage source.

12. The low power output driver of claim 1, wherein the first logic signal and the second logic signal are complementary.

13. A low power output driver comprising:

(a) one of a series-regulated and a switching-mode-regulated reduced voltage source that receives a supply voltage and outputs a regulated reduced voltage that is a lower voltage than the supply voltage;

(b) a first driver input that receives a first logic signal;

(c) a second driver input that receives a second logic signal;

(d) a first driver output that outputs a first output signal;

(e) a second driver output that outputs a second output signal;

(f) a single-ended load connected to both the first driver output and the second driver output;

(g) a first n-type metal oxide semiconductor (NMOS) having a gate, a source and a drain, the source and the drain of the first NMOS being electrically coupled between the reduced voltage V_L and the first driver output, the gate of the first NMOS being electrically coupled to the first driver input;

(h) a second NMOS having a gate, a source and a drain, the source and the drain of the second NMOS being electrically coupled between the first driver output and a constant voltage internal ground, the gate of the second NMOS being electrically coupled to the second driver input;

(i) a third NMOS having a gate, a source and a drain, the source and the drain of the third NMOS being electrically coupled between the reduced voltage V_L and the second driver output, the gate of the third NMOS being electrically coupled to the second driver input; and

(j) a fourth NMOS having a gate, a source and a drain, the source and the drain of the fourth NMOS being electrically coupled between the second driver output and the constant voltage internal ground, the gate of the fourth NMOS being electrically coupled to the first driver input,

when the first driver input is high and the second driver input is low, the first NMOS and the fourth NMOS are gated on, the first driver output is raised to the reduced voltage and the second driver output is pulled down to the constant voltage internal ground,

when the second driver input is high and the first driver input is low, the second NMOS and the third NMOS are gated on, the second driver output is raised to the reduced voltage and the first driver output is pulled down to the constant voltage internal ground.

14. The low power output driver of claim 13, wherein the regulated reduced voltage source includes:

(a1) a voltage source input that receives the supply voltage V_DD; and

(a2) a voltage source output that outputs the regulated reduced voltage V_L.

15. The low power output driver of claim 14, wherein the regulated reduced voltage source further includes:

(a3) a voltage source MOS having a gate, a source and a drain, the source and the drain of the voltage source MOS being electrically coupled between the voltage source input and voltage source output; and

(a4) an operational amplifier having a non-inverting input, an inverting input and an amplifier output, the non-inverting input being electrically coupled to an internal reference, the inverting input being electrically coupled to the voltage source output and the amplifier output being electrically coupled to the gate of the voltage source MOS.

16. The low power output driver of claim 15, wherein the inverting input of the operational amplifier is capacitively coupled to the internal ground.

17. The low power output driver of claim 15, wherein the internal reference includes one of a bandgap reference, a resistance voltage divider, an external reference and an external bandgap.

18. The low power output driver of claim 14, wherein the regulated reduced voltage source further includes:

(a3) a voltage source bipolar transistor, the voltage source bipolar transistor being electrically coupled between the voltage source input and voltage source output; and

(a4) an operational amplifier having a non-inverting input, an inverting input and an amplifier output, the non-inverting input being electrically coupled to an internal reference, the inverting input being electrically coupled to the voltage source output and the amplifier output being electrically coupled to a gate of the voltage source bipolar transistor.

19. The low power output driver of claim 13, wherein the supply voltage is between about 1.0 and about 6.0 volts direct current (VDC) and the reduced voltage is between about 0.1 and about 1.5 VDC.

20. The low power output driver of claim 13, wherein the supply voltage is about 3.3 volts direct current (VDC) and the reduced voltage is about 0.75 VDC.

21. A low power output driver comprising:

(a) one of a series-regulated and a switching-mode-regulated reduced voltage source that receives a supply voltage and outputs a regulated reduced voltage that is a lower voltage than the supply voltage, the reduced voltage source includes a voltage source input that receives the supply voltage and a voltage source output that outputs the regulated reduced voltage V_L, the reduced voltage source including;

(i) a voltage source MOS having a gate, a source and a drain, the source and the drain of the voltage source MOS being electrically coupled between the voltage source input and voltage source output, and

(ii) an operational amplifier having a non-inverting input, an inverting input and an amplifier output, the non-inverting input being electrically coupled to an internal reference, the inverting input being electrically coupled to the voltage source output and the amplifier output being electrically coupled to the gate of the voltage source MOS;

(b) a first driver input that receives a first logic signal;

(c) a second driver input that receives a second logic signal;

(d) a first driver output that outputs a first output signal;

(e) a second driver output that outputs a second output signal;

(f) a first n-type metal oxide semiconductor (NMOS) having a gate, a source and a drain, the source and the drain of the first NMOS being electrically coupled between the reduced voltage V_L and the first driver output, the gate of the first NMOS being electrically coupled to the first driver input;

(g) a second NMOS having a gate, a source and a drain, the source and the drain of the second NMOS being electrically coupled between the first driver output and a constant voltage internal ground, the gate of the second NMOS being electrically coupled to the second driver input;

(h) a third NMOS having a gate, a source and a drain, the source and the drain of the third NMOS being electrically coupled between the reduced voltage V_L and the second driver output, the gate of the third NMOS being electrically coupled to the second driver input; and

(i) a fourth NMOS having a gate, a source and a drain, the source and the drain of the fourth NMOS being electrically coupled between the second driver output and the constant voltage internal ground, the gate of the fourth NMOS being electrically coupled to the first driver input,

when the first driver input is high and the second driver input is low, the first NMOS and the fourth NMOS are gated on, the first driver output is raised to the reduced voltage, the second driver output is pulled down to the constant voltage internal ground, and current through the first NMOS and the fourth NMOS is reduced to zero,

when the second input is high and the first driver input is low, the second NMOS and the third NMOS are gated on, the second driver output is raised to the reduced voltage V_L, the first driver output is pulled down to the constant voltage internal ground, and current through the second NMOS and the third NMOS is reduced to zero, and

the constant voltage internal ground differentiates the driver output raised to the reduced voltage V_L from the driver output pulled down to the constant voltage internal ground.

22. A low power output driver comprising:

(a) one of a series-regulated and a switching-mode-regulated reduced voltage source that receives a supply voltage and outputs a regulated reduced voltage that is a lower voltage than the supply voltage, the reduced voltage source includes a voltage source input that receives the supply voltage and a voltage source output that outputs the regulated reduced voltage V_L, the reduced voltage source including;

(i) a voltage source bipolar transistor, the voltage source bipolar transistor being electrically coupled between the voltage source input and voltage source output, and

(ii) an operational amplifier having a non-inverting input, an inverting input and an amplifier output, the non-inverting input being electrically coupled to an internal reference, the inverting input being electrically coupled to the voltage source output and the amplifier output being electrically coupled to a gate of the voltage source bipolar transistor;

(b) a first driver input that receives a first logic signal;

(c) a second driver input that receives a second logic signal;

(d) a first driver output that outputs a first output signal;

(e) a second driver output that outputs a second output signal;

(f) a first n-type metal oxide semiconductor (NMOS) having a gate, a source and a drain, the source and the drain of the first NMOS being electrically coupled between the reduced voltage V_L and the first driver output, the gate of the first NMOS being electrically coupled to the first driver input;

(g) a second NMOS having a gate, a source and a drain, the source and the drain of the second NMOS being electrically coupled between the first driver output and a constant voltage internal ground, the gate of the second NMOS being electrically coupled to the second driver input;

(h) a third NMOS having a gate, a source and a drain, the source and the drain of the third NMOS being electrically coupled between the reduced voltage V_L and the second driver output, the gate of the third NMOS being electrically coupled to the second driver input; and

(i) a fourth NMOS having a gate, a source and a drain, the source and the drain of the fourth NMOS being electrically coupled between the second driver output and the constant voltage internal ground, the gate of the fourth NMOS being electrically coupled to the first driver input,

when the first driver input is high and the second driver input is low, the first NMOS and the fourth NMOS are gated on, the first driver output is raised to the reduced voltage, the second driver output is pulled down to the constant voltage internal ground, and current through the first NMOS and the fourth NMOS is reduced to zero,

when the second input is high and the first driver input is low, the second NMOS and the third NMOS are gated on, the second driver output is raised to the reduced voltage V_L, the first driver output is pulled down to the constant voltage internal ground, and current through the second NMOS and the third NMOS is reduced to zero, and

the constant voltage internal ground differentiates the driver output raised to the reduced voltage V_L from the driver output pulled down to the constant voltage internal ground.