TW201743561A - Level shifter - Google Patents

Abstract

A level shifter is capable of transferring an input signal to an output signal. When the input signal changes from a ground voltage to a first supplying voltage, a first current mirror and a first current path control circuit of the level shifter are activated to pull up an output signal to a second supplying voltage. When the input signal changes from the first supplying voltage to the ground voltage, a second current mirror and a second current path control circuit of the level shifter are activated to pull up an inverted output signal to the second supplying voltage.

Description

Converter

The present invention relates to an interface circuit, and more particularly to a voltage converter in an interface circuit.

The converter can receive an input signal with a small signal range and convert it correspondingly into an output signal with a large signal range, which is an important building block in the interface circuit. For example, in an IC chip, a specific signal is converted from a signal range of a core voltage to a signal range of an input-input voltage (IO voltage). Basically, the core voltage can range from 0 to 1.5 volts, while the input and output voltages range from 0 to 3.3 volts. In order to convert between the two signal ranges, a transducer is required to convert an input signal of 0 to 1.5 volts into an output signal of 0 to 3.3 volts.

Please refer to FIG. 1 , which is a conventional pressure converter. The converter 10 can convert the input signal IN having a signal range of the voltage VDDL to GND into an output signal OUT having a signal range between the voltages VDDH and GND. The power supply voltage VDDL may be, for example, 1.5 volts, the power supply voltage VDDH may be, for example, 3.3 volts, and the ground voltage GND is 0 volts, wherein the power supply voltage VDDH is greater than the power supply voltage VDDL, and the power supply voltage VDDL is greater than the ground voltage GND.

The converter 10 includes a P-type transistor MP1, a P-type transistor MP2, an N-type transistor MN1, and an N-type transistor MN2, wherein the source of the P-type transistor MP1 is connected to the power supply voltage VDDH, and the drain is connected to Node a, and the gate are connected to node b. The P-type transistor MP2 source is connected to the power supply voltage VDDH, the drain is connected to the node b, and the gate is connected to the node a.

Furthermore, the N-type transistor MN1 is connected to the node a, the source is connected to the ground voltage GND, and the gate receives the input signal IN. The N-type transistor MN2 is connected to the node b, the source is connected to the ground voltage GND, and the gate receives the inverted input signal INB. The node a is further used as a first output terminal for generating an inverted output signal OUTB, and the node b is further configured as a second output terminal for generating an output signal OUT.

When the input signal IN of the converter 10 is 1.5 volts and the inverted input signal INB is 0 volts, the N-type transistor MN1 and the P-type transistor MP2 are turned on, and the N-type transistor MN2 and P-type The transistor MP1 is turned off. Therefore, the output signal OUT is a power supply voltage VDDH of 3.3 volts, and the inverted output signal OUTB is a ground voltage GND of 0 volts.

When the input signal IN of the converter 10 is 0 volts and the inverted input signal INB is 1.5 volts, the N-type transistor MN1 and the P-type transistor MP2 are turned off, and the N-type transistor MN2 and P-type The transistor MP1 is turned on. Therefore, the output signal OUT is a ground voltage GND of 0 volts, and the inverted output signal OUTB is a power supply voltage VDDH of 3.3 volts.

The invention relates to a voltage converter for converting an input signal into an output signal, comprising: a first transistor having a first drain connected to a first node, and a first gate receiving the input signal And a first source connected to a first power voltage; a second transistor having a second drain connected to a second node, a second gate receiving an inverted input signal, and a second The second source is connected to the first power voltage; a third transistor has a third source connected to a second power voltage, a third drain is connected to the first node, and a third gate is connected To the second node; a fourth transistor having a fourth source connected to the second supply voltage, a fourth drain connected to the second node, and a fourth gate connected to the first node The first node is used as a first output to generate an inverted output signal, and the second node is used as a second output to generate the output signal; a first current mirror is coupled to the second a power supply voltage, wherein the first current mirror has a first The current input terminal is connected to a third node, and a first current mirror is connected to the first node; a first current path control circuit is connected between the third node and the first power voltage, according to the An inverted input signal is coupled to the output signal; a second current mirror is coupled to the second supply voltage, wherein the second current mirror has a second current input coupled to a fourth node, and a second current The mirror end is connected to the second node; and a second current path control circuit is connected between the fourth node and the first power voltage, and operates according to the input signal and the inverted output signal.

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

10, 20‧‧‧Transducer

21‧‧‧Inverter

22, 24‧‧‧current mirror

26, 28‧‧‧ Current path control circuit

MN1~MN6‧‧‧N type transistor

MP1~MP6‧‧‧P type transistor

Figure 1 shows a conventional converter.

Figure 2 is a view of the pressure converter of the present invention.

Figure 3 is a schematic diagram showing the relevant signals of the converter of the present invention.

In order to make IC chips faster and more power efficient, the core voltage in IC chips is getting lower and lower. The converter of the present invention is still capable of operating normally at a core voltage range of 0 to 0.7 volts.

Please refer to FIG. 2, which illustrates the converter of the present invention. The converter 20 can convert the input signal IN having a signal range of the voltages VDDL to VSS into the output signal OUT of the signal range between the voltages VDDH to VSS. The power supply voltage VDDL may be, for example, 0.7 volts, the power supply voltage VDDH may be, for example, 3.3 volts, and the power supply voltage VSS may be, for example, 0 volts; that is, the power supply voltage VDDH is greater than the power supply voltage VDDL, and the power supply voltage VDDL is greater than the power supply voltage VSS.

The converter 20 includes a P-type transistor MP1, a P-type transistor MP2, an N-type transistor MN1, an N-type transistor MN2, current mirrors 22 and 24, and current path control circuits 26 and 28. In addition, an inverter 21 operating between the power supply voltage VDDL and the power supply voltage VSS receives an input signal IN at its input terminal and an inverted input signal INB at its output terminal.

In the converter 20, the source of the P-type transistor MP1 is connected to the power supply voltage VDDH; the drain is connected to the node a; and the gate is connected to the node b. The P-type transistor MP2 source is connected to the power supply voltage VDDH; the drain is connected to the node b; and the gate is connected to the node a.

Furthermore, the N-type transistor MN1 is connected to the node a, the source is connected to the power supply voltage VSS, and the gate receives the input signal IN. The N-type transistor MN2 is connected to the node b; the source is connected to the power supply voltage VSS; and the gate receives the inverted input signal INB. The node a is further used as the first output terminal to generate the inverted output signal OUTB; the node b is further used as the second output terminal to generate the output signal OUT.

The current mirror 22 is connected to the power supply voltage VDDH, and the current mirror 22 includes a current input terminal connected to the node c and a current mirroring terminal connected to the node a. In addition, the current mirror 24 is connected to the power supply voltage VDDH, and the current mirror 24 includes a current input terminal connected to the node d and a current mirror terminal connected to the node b.

The current path control circuit 26 includes two N-type transistors MN3 and MN4 connected in series between the node c and the power supply voltage VSS, and the gate of the N-type transistor MN3 receives the inverted input signal INB, The gate of the N-type transistor MN4 receives the output signal OUT. In addition, the current path control circuit 28 includes two N-type transistors MN5 and MN6 connected in series between the node d and the power supply voltage VSS. The gate of the N-type transistor MN5 receives the input signal IN, and the gate of the N-type transistor MN6. The pole receives the inverted output signal OUTB.

Please refer to FIG. 3, which is a schematic diagram of related signals of the converter of the present invention. At time t1, the input signal IN of the converter 20 is changed from 0 volts to 0.7 volts, the N-type transistor MN1 is turned on and the N-type transistor MN2 is turned off.

The time period t1 to the time point t2 is a first transient period. At the beginning of the first transient period, the input signal IN is 0.7 volts and the inverted output signal OUTB is 3.3 volts, causing the current path control circuit 28 to operate. (activate). At the same time, during the first transient state, the current path control circuit 26 does not operate because the inverted input signal INB is 0 volts.

When the current path control circuit 28 operates, the voltage Vd of the node d gradually rises from 0 volts, and the current path control circuit 28 generates a control current to the current input terminal of the current mirror 24, so that the node b (meaning the output signal OUT) is Pull up to 3.3 volts and cause the P-type transistor MP1 to turn off, while node a (ie, the inverted output signal OUTB) is pulled down to 0 volts.

The time period t2 to the time point t3 is the first steady state period, the input signal IN is 0.7 volts, the inverted input signal INB is 0 volts, the output signal OUT is 3.3 volts, and the inverted output signal OUTB is 0 volts. At this time, the P-type transistor MP1 is turned off, the P-type transistor MP2 is turned on, the N-type transistor MN1 is turned on, the N-type transistor MN2 is turned off, and the current path is controlled. Circuits 26 and 28 do not operate. Obviously, during the first steady state, there is no leakage current path in the converter 20, which can effectively reduce the power consumption of the converter 20.

At time t3, the input signal IN of the converter 20 is changed from 0.7 volts to 0 volts, the N-type transistor MN1 is turned off and the N-type transistor MN2 is turned on.

The second transient period is from time t3 to time t4. At the beginning of the second transient period, the inverting input signal INB is 0.7 volts and the output signal OUT is 3.3 volts, causing the current path control circuit 26 to activate. At the same time, during the second transient state, the current path control circuit 28 does not operate because the input signal IN is 0 volts.

When the current path control circuit 26 operates, the voltage Vc of the node c is gradually increased by 0 volts, and the current path control circuit 26 generates a control current to the current input terminal of the current mirror 22, so that the node a (ie, the inverted output signal) OUTB) is pulled up to 3.3 volts and causes P-type transistor MP2 to turn off, while node b (meaning output signal OUT) is pulled down to 0 volts.

After the time point t4 is the second steady state period, the input signal IN is 0 volts, the inverted input signal INB is 0.7 volts, the output signal OUT is 0 volts, and the inverted output signal OUTB is 3.3 volts. At this time, the P-type transistor MP1 is turned on, the P-type transistor MP2 is turned off, the N-type transistor MN1 is turned off, the N-type transistor MN2 is turned on, and the current path is controlled. Circuits 26 and 28 do not operate. Obviously, during the second steady state, there is no leakage path in the converter 20, which can effectively reduce the power consumption of the converter 20.

When the input signal IN is changed from 0 volt to 0.7 volt again, the operation principle is the same as that after the above-mentioned time point t1, and will not be described again.

As apparent from the above description, when the input signal IN is switched from the power supply voltage VSS to the power supply voltage VDDL, the current mirror 24 and the current path control circuit 28 pull up the output signal OUT to the power supply voltage VDDH. When the input signal IN is switched from the power supply voltage VDDL to the power supply voltage VSS, the inverted output signal INB is pulled up to the second voltage by the current mirror 22 and the current path control circuit 28.

Furthermore, an advantage of the present invention is that a converter is provided in which the input signal IN and the inverted input signal INB can operate in an extremely low signal range. According to an embodiment of the present invention, the voltage converter of the present invention can still operate normally when the power supply voltage VDDL drops to 0.4 volts, and thus is well suited for use on an IC chip having a very low core voltage.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

20‧‧‧Transducer

21‧‧‧Inverter

22, 24‧‧‧current mirror

26, 28‧‧‧ Current path control circuit

MN1~MN6‧‧‧N type transistor

MP1~MP6‧‧‧P type transistor

Claims (8)

A voltage converter for converting an input signal into an output signal, comprising: a first transistor having a first drain connected to a first node, a first gate receiving the input signal, and a first The source is connected to a first power voltage; a second transistor has a second drain connected to a second node, a second gate receives an inverted input signal, and a second source is coupled to the second source The first power voltage; a third transistor having a third source connected to a second power voltage, a third drain connected to the first node, and a third gate connected to the second node a fourth transistor having a fourth source connected to the second supply voltage, a fourth drain connected to the second node, and a fourth gate connected to the first node, wherein the first The node acts as a first output to generate an inverted output signal, and the second node acts as a second output to generate the output signal; a first current mirror is coupled to the second supply voltage, wherein the The first current mirror has a first current input terminal Up to a third node, and a first current mirror end connected to the first node; a first current path control circuit connected between the third node and the first supply voltage, according to the inverted input a signal is coupled to the output signal; a second current mirror is coupled to the second supply voltage, wherein the second current mirror has a second current input coupled to a fourth node, and a second current mirror connection And the second current path control circuit is connected between the fourth node and the first power supply voltage, and operates according to the input signal and the inverted output signal. The converter of claim 1, wherein the first transistor and the second transistor are N-type transistors, and the third transistor and the fourth transistor are P-type transistors. The converter of claim 1, further comprising an inverter connected to a third power voltage and the first power voltage, the inverter receiving the input signal to generate the inverted input signal . The converter of claim 3, wherein the second power voltage is greater than the third power voltage, and the third power voltage is greater than the first power voltage. The voltage converter of claim 1, wherein the first current path control circuit comprises a fifth transistor and a sixth transistor connected in series between the third node and the first power voltage. A fifth gate of the fifth transistor receives the inverted input signal, and a sixth gate of the sixth transistor receives the output signal. The voltage converter of claim 5, wherein the first current mirror comprises: a seventh transistor having a seventh source connected to the second power voltage, and a seventh drain connected to the a first node, and a seventh gate connected to the third node; An eighth transistor having an eighth source coupled to the second supply voltage, an eighth drain coupled to the third node, and an eighth gate coupled to the third node. The converter of claim 1, wherein the second current path control circuit comprises a ninth transistor and a tenth transistor connected in series between the fourth node and the first power voltage A ninth gate of the ninth transistor receives the input signal, and a tenth gate of the tenth transistor receives the inverted output signal. The voltage converter of claim 7, wherein the second current mirror comprises: an eleventh transistor having an eleventh source connected to the second power supply voltage, an eleventh dipole Connected to the second node, and an eleventh gate connected to the fourth node; and a twelfth transistor having a twelfth source connected to the second supply voltage, a twelfth drain Connected to the fourth node, and a twelfth gate is connected to the fourth node.