Fast Voltage Level Shifter Circuit

• US 20110181340A1
• Filed: 01/27/2011
• Published: 07/28/2011
• Est. Priority Date: 01/27/2010
• Status: Active Grant

• Current Assignee: Solaredge Technologies Incorporated
• Original Assignee: Solaredge Technologies Incorporated
• Inventors: Gazit, Meir
• Granted Patent: US 8,766,696 B2
• Time in Patent Office: Days
• US Class Current: 327/333
• CPC Class Codes: H03K 19/0185 using field effect transistors only
• CPC Class Codes: H03K 19/018507 Interface arrangements
• CPC Class Codes: H03K 19/018521 of complementary type, e.g. CMOS
• CPC Class Codes: H03K 3/356 Bistable circuits
• CPC Class Codes: H03K 3/356104 using complementary field-effect transistors H03K3/35625 takes precedence

Abstract

A voltage level shifting circuit with an input terminal and an output terminal. The level shifting circuit has a field-effect transistor (FET) switch with a gate attached to the input terminal, a drain attached to the output terminal and a source attached to a current changing mechanism. The current changing mechanism includes a current mirror circuit having an output connected between the source and an electrical earth. The output of the current mirror circuit is preferably adapted to change a current flowing between the drain and the source based on an input voltage applied to the gate.

Claims

1. A voltage level shifting circuit with an input terminal and an output terminal, the level shifting circuit comprising:

a field-effect transistor (FET) switch including;

a gate attached to said input terminal;

a drain attached to said output terminal; and

a source;

a current changing mechanism, wherein said source is attached to said current changing mechanism;

wherein said current changing mechanism includes;

a current mirror circuit having an output connected between said source and an electrical earth;

wherein said output of said current mirror circuit is adapted to change a current flowing between said drain and said source based on an input voltage applied to said gate;

wherein said input voltage produces an output voltage on said output terminal based on said current; and

a charge storage circuit operatively attached to said input terminal and an input of said current mirror circuit.

2. The level switching circuit of claim 1, wherein the charge storage circuit includes:

an inverting amplifier with an input connected to said input terminal;

a second inverting amplifier with a second input connected to an output of said inverting amplifier.

3. The level switching circuit of claim 1, wherein the charge storage circuit includes:

a capacitor connected to an anode of a diode;

wherein a cathode of said diode is connected to said input of said current mirror circuit; and

a second diode with a second cathode connected to said anode of said diode and a second anode connected to said electrical earth.

4. The level switching circuit of claim 1, wherein the charge storage circuit includes:

an inverting amplifier with an input connected to said input terminal;

a capacitor connected between an output of said inverting amplifier and an anode of a diode;

wherein a cathode of said diode is connected to said input of said current mirror circuit; and

a second diode with a second cathode connected to said anode of said diode and a second anode connected to said electrical earth;

a second inverting amplifier with a second input connected to said output of said inverting amplifier;

a second capacitor connected between a second output of said second inverting amplifier and a third anode of a third diode;

wherein a third cathode of said third diode is connected to said input of said current mirror circuit; and

a fourth diode with a fourth cathode connected to said third anode of said third diode and a third anode connected to said electrical earth.

5. The level switching circuit of claim 1, wherein the charge storage circuit includes selectively either a capacitor or battery.

6. A voltage level shifting circuit with an input terminal and an output terminal, the level shifting circuit comprising:

a switch driven by an input voltage applied to said input terminal to produce an output voltage on said output terminal based on a current drawn through said switch; and

a current changing mechanism operatively connected to said switch, wherein said current changing mechanism is adapted for changing said current through said switch;

wherein said current changing mechanism is adapted to change said current when said switch is switched.

7. The level switching circuit of claim 6, wherein said switch is selected from the group consisting of:

silicon controlled rectifier (SCR), insulated gate bipolar junction transistor (IGBT), bipolar junction transistor (BJT), field effect transistor (FET), junction field effect transistor (JFET), switching diode, electrical relay, reed relay, solid state relay, insulated gate field effect transistor (IGFET), diode for alternating current (DIAC), and triode for alternating current TRIAC.

8. The level switching circuit of claim 6, wherein said current changing mechanism is adapted to provide a current control signal to a leg of said switch.

9. The level switching circuit of claim 6, further comprising:

a current mirror circuit having an output connected between said switch and an electrical earth;

a charge storage circuit operatively attached to said input terminal and an input of said current mirror circuit; and

a second charge storage circuit operatively attached to said output terminal.

10. The level switching circuit of claim 9, wherein the second charge storage circuit includes selectively either a capacitor or a battery.

11. A method to operate a voltage level shifting circuit, wherein the level shifting circuit includes a switch which has an input terminal and an output terminal, and a current mirror circuit having a current-mirror circuit output, wherein the switch is connected in series with the current-mirror circuit output and an electrical earth, wherein a charge storage circuit is attached to said input terminal and an input of said current mirror circuit, the method comprising:

applying a voltage on said input terminal thereby driving a current through said switch and said current-mirror circuit output;

wherein said driving provides a voltage on the output terminal; and

increasing said current by a discharge of said charge storage circuit into said input of said current mirror circuit.

12. The method of claim 11, further comprising:

switching the switch on, wherein said increasing is performed when switching the switch on.

13. The method of claim 11, further comprising:

decreasing said current by a charge of said charge storage circuit from said input of said current mirror circuit.

14. The method of claim 11, further comprising:

switching the switch on, wherein said increasing is performed at a time just prior to said switching the switch on.

15. The method of claim 11, wherein said current is a minimal value prior to said applying.

16. The method of claim 11, further comprising:

charging said charge storage circuit prior to said applying.

17. The method of claim 16, further comprising:

switching said switch off, wherein said charging is when said switch is off.