CN100429600C - Current and Voltage Reference Circuits - Google Patents

Abstract

A current and voltage reference circuit includes a current bias circuit and a voltage reference circuit. The current bias circuit receives the driving signal, provides a reference current, a bias signal and a start signal when the driving signal is in an enable state, and provides a first preset voltage and a second preset voltage when the driving signal is in a stop state. The voltage reference circuit is connected to the current bias circuit, and enters an on state and provides a reference voltage if receiving the bias signal and the driving signal, and enters an off state if receiving the first preset voltage and the second preset voltage.

Description

Current and Voltage Reference Circuits

technical field

The invention relates to a current and voltage reference circuit, and in particular to a current and voltage reference circuit suitable for handheld electronic devices.

Background technique

As the application of handheld electronic devices is becoming more and more extensive, the requirement for battery life is also increasing. Therefore, how to reduce the power consumption of the components of the handheld electronic device in the standby or off state has become a major issue in current technology. In analog circuits, the static current consumption of current and voltage reference circuits is often the technical bottleneck. Therefore, we hope to develop a current and voltage reference circuit that is easy to turn on and off, and can Consumes very low quiescent current.

The U.S. Patent No. 5949227 application proposes a circuit as shown in Figure 1, a startup (startup) circuit 101 is used to start a voltage reference circuit 103, and a startup stop (startup disable) circuit 102 is used to separate the startup circuit 101 and the voltage reference circuit when it is closed 103. However, the startup and cutoff circuit 102 proposed in this patent cannot completely shut down the current, that is to say, there is still current consumption when it is turned off.

The paper "A CMOS Bandgap Reference Circuit with Sub-1-V Operation" published by Hironori Banba and Hitoshi Shiga et al. in Journal of Solid-State Circuit, vol.34, no.5, pp.670-674, May 1999 mainly proposes a A bandgap reference circuit for low voltage use. The starting method of its frequency band gap reference circuit is to use N-channel metal oxide semiconductor field effect transistor (n-channel metal oxide semiconductor field effect transistor, referred to as NMOS transistor) and start (power-on reset) signal to make the frequency band gap reference circuit When the circuit is initially powered on, the entire circuit can be started. Although this paper proposes the implementation method and start-up method of the low-voltage bandgap reference circuit, it does not provide a shutdown method.

Another paper was published by Piero Malcovati and Franco Maloberti et al. in Journal of Solid-State Circuit, vol.36, no.7, pp.1076-1081, July 2001 "Curvature-Compensated BiCMOS Bandgap with 1-V SupplyVoltage ". This paper mainly proposes the design method of the operational amplifier (operational amplifier) and the start-up function in the low-voltage bandgap reference circuit under low voltage, but does not propose a shutdown method. In addition, the above start-up method requires a BiCMOS process, that is, a composite process of a bipolar junction transistor (BJT transistor for short) and a complementary metal oxide semiconductor transistor (complementary MOS, CMOS for short).

As can be seen from the above description, the current technology can not meet our expectations.

Contents of the invention

The purpose of the present invention is to provide a current and voltage reference circuit, which has a complete turn-on and turn-off function, consumes almost no current when it is turned off, can prolong the use time of hand-held electronic devices, and can be realized only by CMOS technology.

To achieve the above and other objectives, the present invention provides a current and voltage reference circuit, including a current bias circuit and a voltage reference circuit. The current bias circuit receives the driving signal, provides a reference current, a bias signal and a start signal when the driving signal is in an enabled state, and provides a first preset voltage and a second preset voltage when the driving signal is in an off state. The voltage reference circuit is connected to the current bias circuit. If it receives a bias signal and a start signal, it enters an on state and provides a reference voltage. If it receives a first preset voltage and a second preset voltage, it enters an off state.

In one embodiment of the current and voltage reference circuit, the current bias circuit further includes a startup circuit, a first isolator, a constant transconductance bias circuit, and a second isolator. The starting circuit receives the status signal, and outputs the starting signal if the status signal is in the off state. The first isolator receives the driving signal, and the self-starting circuit receives the starting signal, and outputs the starting signal if the driving signal is in the enabled state, and outputs the third preset voltage if the driving signal is in the cut-off state. A constant transconductance bias (constant gm bias or constant transconductance bias) circuit provides a state signal to the start-up circuit according to its state, and is connected to the first isolator. If the start signal is received from the first isolator, it enters into an on state and outputs reference current and bias voltage signals; if it receives a third preset voltage from the first isolator, it enters into an off state. Finally, the second isolator receives the drive signal, and if the drive signal is enabled, then transmits the bias signal output by the constant transconductance bias circuit to the voltage reference circuit, and transmits the start signal output by the first isolator to the voltage reference circuit. On the contrary, if the driving signal is in cut-off state, the first preset voltage and the second preset voltage are output to the voltage reference circuit.

In one embodiment of the above-mentioned current and voltage reference circuit, if the driving signal is in a cut-off state, the first isolator isolates the start-up circuit, the constant transconductance bias circuit, and the second isolator. Also, the second isolator isolates the constant transconductance bias circuit, the first isolator, and the voltage reference circuit.

According to the preferred embodiment of the present invention, the present invention starts the constant transconductance bias circuit with the startup circuit, and then starts the voltage reference circuit with the startup circuit and the constant transconductance bias circuit. As for shutdown, the present invention turns off the constant transconductance bias circuit and the voltage reference circuit with the preset voltage output by the isolator itself. Therefore, the present invention has complete opening and closing functions.

In addition, when it is turned off, the isolator of the present invention will isolate the start-up circuit, the constant transconductance bias circuit, and the voltage reference circuit, and completely block the current, so the current and voltage reference circuits proposed by the present invention consume almost no current when they are turned off. , can prolong the use time of handheld electronic devices. Moreover, the present invention does not use BJT transistors, so it can be realized only by CMOS technology.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, preferred embodiments of the present invention will be described in detail below together with the accompanying drawings.

Description of drawings

FIG. 1 is a schematic circuit diagram of the background technology.

FIG. 2 is a circuit diagram of a current and voltage reference circuit according to an embodiment of the invention.

3 and 4 are circuit diagrams of the isolator in FIG. 2 .

Description of main component marking

101: start circuit

102: Start cut-off circuit

103: Voltage reference circuit

200: current and voltage reference circuit

201: Current bias circuit

202: Voltage reference circuit

203: start circuit

204: Isolator

205: Constant transconductance bias circuit

206: Isolator

207: First switch circuit

208: Second switch circuit

209: Band Gap Reference Circuit

301, 302, 401, 402: Multiplexers

GND: ground wire

NS: start transistor

P1～P6: PMOS transistors

VDD: voltage source

Detailed ways

FIG. 2 is a schematic circuit diagram of a current and voltage reference circuit 200 according to an embodiment of the invention. The current and voltage reference circuit 200 includes a current bias circuit 201 and a voltage reference circuit 202 connected to each other.

The current bias circuit 201 includes a startup circuit 203 , an isolator 204 , a constant transconductance bias circuit 205 , and an isolator 206 . The isolator 204 is connected to the startup circuit 203 . The constant transconductance bias circuit 205 is connected to the startup circuit 203 and the isolator 204 . The isolator 206 is connected to the constant transconductance bias circuit 205 and the isolator 204 .

On the other hand, the voltage reference circuit 202 includes switch circuits 207 and 208 , a start transistor NS (in this embodiment, an NMOS transistor), and a bandgap reference circuit (bandgap reference circuit) 209 . The switch circuit 207 is connected to a voltage source VDD. The switch circuit 208 is connected to the switch circuit 207 and the isolator 206 . The enable transistor NS is connected to the isolator 206 and the switch circuit 207 . Finally, the bandgap reference circuit 209 is connected between the switch circuits 207, 208, the enable transistor NS, and the ground line GND.

The current and voltage reference circuit 200 has two states of on and off. In the on state, the isolators 204 and 206 turn on the startup circuit 203 , the constant transconductance bias circuit 205 , and the bandgap reference circuit 209 . The constant transconductance bias circuit 205 is turned on and outputs the reference current IREF. The bandgap reference circuit 209 will also enter the on state, and output the reference voltage VREF. On the other hand, when the current and voltage reference circuit 200 is in the off state, the isolators 204 and 206 isolate the current between the start-up circuit 203 , the constant transconductance bias circuit 205 , and the bandgap reference circuit 209 . The constant transconductance bias circuit 205 and the bandgap reference circuit 209 will be turned off accordingly, and the bias currents in the constant transconductance bias circuit 205 and the bandgap reference circuit 209 will approach zero. The startup and shutdown process of the entire current and voltage reference circuit 200 will be described in detail below.

When the current and voltage reference circuit 200 is turned off and the power supply rises from zero to a certain fixed voltage, the current and voltage reference circuit 200 starts to start. First, the driving signal 220 will enter the enable state, so that the isolators 204 and 206 turn on the startup circuit 203 , the constant transconductance bias circuit 205 , and the bandgap reference circuit 209 . Then the constant transconductance bias circuit 205 provides the status signal 223 to the startup circuit 203 . The content of the state signal 223 is to reflect the state of the constant transconductance bias circuit 205. At this time, the constant transconductance bias circuit 205 is still closed, so the state signal 223 is naturally also in the closed state.

The start-up circuit 203 outputs a start-up signal 221 upon receiving the off-state status signal 223 . The isolator 204 will pass the enable signal 221 to the constant transconductance bias circuit 205 . After receiving the start signal 221 , the constant transconductance bias circuit 205 enters into an on state, and outputs the reference current IREF and the bias signal 222 . The isolator 206 transmits the bias signal 222 to the switch circuit 208 , so that the switch circuit 208 turns on the switch circuit 207 and the bandgap reference circuit 209 .

On the other hand, the isolators 204 and 206 transmit the start-up signal 221 of the start-up circuit 203 to the start-up transistor NS to turn on the start-up transistor NS. After being turned on, the low potential of the drain of the startup transistor NS makes the switch circuit 207 turn on the voltage source VDD and the switch circuit 208 . At this time, the start-up transistor NS and the switch circuits 207 and 208 are all turned on, and the bandgap reference circuit 209 is turned on, and outputs the reference voltage VREF.

Next, if the current and voltage reference circuit 200 is to turn from the on state to the off state, firstly the driving signal 220 will enter the off state, so that the isolators 204 and 206 isolate the start-up circuit 203, the constant transconductance bias circuit 205, and the bandgap reference current between circuit 209. Then the isolator 204 outputs a third preset voltage to turn off the constant transconductance bias circuit 205 . Although the state signal 223 will cause the startup circuit 203 to output the startup signal 221 , because the isolator 204 has isolated the startup circuit 203 and the constant transconductance bias circuit 205 , the constant transconductance bias circuit 205 will not start up again.

On the other hand, the isolator 206 outputs a first preset voltage to turn off the switch circuit 208 , and outputs a second preset voltage to turn off the start-up transistor NS. Once the start-up transistor NS is turned off, the switch circuit 207 is also turned off. At this time, because the start-up transistor NS and the switch circuits 207 and 208 have been turned off, the bandgap reference circuit 209 will also enter the off state.

Next please refer to FIG. 3 , which is a schematic circuit diagram of the isolator 204 . The isolator 204 mainly includes multiplexers 301 and 302 . Both the multiplexers 301 and 302 receive the driving signal 220 . When the drive signal 220 is in the enabled state, the multiplexer 301 will transmit the start-up signal 221 of the start-up circuit 203 to the constant transconductance bias circuit 205, and the multiplexer 302 will pass the above-mentioned start-up signal 221 to the isolator 206. Conversely, when the driving signal 220 is in the cut-off state, the multiplexer 301 will deliver the third preset voltage 313 to the constant transconductance bias circuit 205, and the multiplexer 302 will connect its output terminal to the ground GND . It is easy to see from FIG. 2 and FIG. 3 that when the startup signal 220 is off, the isolator 204 can indeed isolate the startup circuit 203 , the constant transconductance bias circuit 205 , and the isolator 206 .

Next, please refer to FIG. 4 , which is a schematic circuit diagram of the isolator 206 . The isolator 206 mainly includes multiplexers 401 and 402 . Both the multiplexers 401 and 402 receive the driving signal 220 . When the drive signal 220 is in the enabled state, the multiplexer 401 will pass the bias signal 222 of the constant transconductance bias circuit 205 to the switch circuit 208, and the multiplexer 402 will pass the signal from the multiplexer 302 Enable signal 221 to enable transistor NS. Conversely, when the driving signal 220 is in the off state, the multiplexer 401 transmits the first predetermined voltage 411 to the switch circuit 208 , and the multiplexer 402 transmits the second predetermined voltage 412 to the enable transistor NS. It is easy to see from FIG. 2 and FIG. 4 that when the enable signal 220 is off, the isolator 206 can indeed isolate the constant transconductance bias circuit 205 , the isolator 204 , and the bandgap reference circuit 209 .

To sum up, the present invention uses the startup circuit to start the constant transconductance bias circuit, and then uses the startup circuit and the constant transconductance bias circuit to start the bandgap reference circuit. As for shutting down, the present invention shuts down the constant transconductance bias circuit and the frequency band gap reference circuit with the preset voltage output by the isolator itself. Therefore, the present invention has complete opening and closing functions.

In addition, when it is turned off, the isolator of the present invention will isolate the start-up circuit, the constant transconductance bias circuit, and the bandgap reference circuit, and completely block the current, so the current and voltage reference circuits proposed by the present invention consume almost no energy when they are turned off. current, which can prolong the use time of handheld electronic devices. Moreover, the present invention does not use BJT transistors, so it can be realized only by CMOS technology.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some modifications and improvements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the claims.

Claims (9)

1. A current and voltage reference circuit, characterized in that it comprises: a current bias circuit, receiving a driving signal, providing a reference current, a bias signal and a start signal when the driving signal is in an enabled state, and providing a first preset voltage and a second preset voltage when the driving signal is in an off state; as well as The voltage reference circuit is connected to the current bias circuit. If it receives the bias signal and the start signal, it will enter the open state and provide a reference voltage. If it receives the first preset voltage and the second preset voltage, it will enter Disabled, The current bias circuit also includes: Start the circuit, receive the status signal, and output the startup signal if the status signal is off; The first isolator receives the driving signal, and receives the starting signal from the starting circuit, and outputs the starting signal if the driving signal is in an enabled state, and outputs a third preset voltage if the driving signal is in an off state; The constant transconductance bias circuit provides the status signal to the start-up circuit according to the state of the constant transconductance bias circuit, and is connected to the first isolator. If the start-up signal is received from the first isolator, it enters the start-up state. state and output the reference current and the bias signal, if the third preset voltage is received from the first isolator, it enters the shutdown state; and The second isolator receives the drive signal, and if the drive signal is in a permitted state, then transmits the bias signal output by the constant transconductance bias circuit to the voltage reference circuit, and transmits the activation output by the first isolator The signal is sent to the voltage reference circuit, and if the driving signal is in an off state, the first preset voltage and the second preset voltage are output to the voltage reference circuit. 2. The current and voltage reference circuit according to claim 1, wherein if the constant transconductance bias circuit enters an on state, the status signal also enters an on state, and if the constant transconductance bias circuit enters an off state , the status signal also enters the off state. 3. The current and voltage reference circuit according to claim 1, wherein if the driving signal is in an off state, the first isolator isolates the start-up circuit, the constant transconductance bias circuit, and the second isolator and the second isolator isolates the constant transconductance bias circuit, the first isolator, and the voltage reference circuit. 4. The current and voltage reference circuit according to claim 1, wherein the first isolator further comprises: The first multiplexer receives the third preset voltage, receives the startup signal from the startup circuit, and transmits the third preset voltage or the startup signal to the constant transconductance bias circuit according to the driving signal. 5. The current and voltage reference circuit according to claim 1, wherein the first isolator further comprises: The second multiplexer receives the start signal from the start circuit, and transmits the start signal to the second isolator when the drive signal is in an enabling state. 6. The current and voltage reference circuit according to claim 1, wherein the second isolator further comprises: The third multiplexer receives the first preset voltage, receives the bias signal from the constant transconductance bias circuit, and transmits the first preset voltage or the bias signal to the voltage according to the drive signal Reference circuit. 7. The current and voltage reference circuit according to claim 1, wherein the second isolator further comprises: The fourth multiplexer receives the second preset voltage, receives the startup signal from the first isolator, and transmits the second preset voltage or the startup signal to the voltage reference circuit according to the drive signal. 8. A current and voltage reference circuit, characterized in that it comprises: a current bias circuit, receiving a driving signal, providing a reference current, a bias signal and a start signal when the driving signal is in an enabled state, and providing a first preset voltage and a second preset voltage when the driving signal is in an off state; as well as The voltage reference circuit is connected to the current bias circuit. If it receives the bias signal and the start signal, it will enter the open state and provide a reference voltage. If it receives the first preset voltage and the second preset voltage, it will enter Disabled, The voltage reference circuit also includes: A start transistor is connected to the current bias circuit and the ground wire; a first switch circuit connected to a voltage source and the startup transistor; a second switch circuit connected to the current bias circuit and the first switch circuit; and a bandgap reference circuit connected to the second switch circuit and the enable transistor; wherein The start-up transistor receives the start-up signal or the second preset voltage from the current bias circuit, and turns on the first switch circuit, the frequency band gap reference circuit, and the ground if receiving the start-up signal, a second preset voltage, disconnecting the first switch circuit, the bandgap reference circuit, and the ground wire; The first switch circuit turns on or off the voltage source and the second switch circuit according to the on and off states of the startup transistor; The second switch circuit receives the bias signal or the first preset voltage from the current bias circuit, if it receives the bias signal, it turns on the first switch circuit and the frequency band gap reference circuit, if it receives the first preset voltage a preset voltage, disconnecting the first switch circuit and the bandgap reference circuit; If the start-up transistor, the first switch circuit, and the second switch circuit are all turned on, the bandgap reference circuit enters an open state and outputs the reference voltage; If the enable transistor, the first switch circuit, and the second switch circuit are all turned off, the bandgap reference circuit enters an off state. 9. The current and voltage reference circuit according to claim 8, wherein when the enable transistor is turned on, the first switch circuit turns on the voltage source and the second switch circuit, and when the enable transistor is turned off , the first switch circuit disconnects the voltage source and the second switch circuit.

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