JP2002033649A - Electric circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electric circuit that can reduce a start time of an internal power supply and a recovery time on the occurrence of a voltage drop of an external power supply. SOLUTION: The electric circuit is provided with an internal power supply resulting from caused by dropping a voltage of an external power supply by a voltage drop circuit 8, a reference voltage generating circuit 5 that generates a reference voltage as an index of a drop voltage, a main circuit including a 1st sequential circuit 21 and a 2nd sequential circuit 22 and receiving each power supply, a power-on reset circuit detecting that a voltage of the external power supply is less than a fixed value to output a 1st detection signal, a circuit including a 3rd sequential circuit 15, and a 2nd detection circuit 11 that outputs a 2nd detection signal when a difference between the reference voltage and the voltage of the internal power supply is higher than a prescribed value and an OR signal between the difference and the 1st detection signal initializes the 3rd sequential circuit 15. The 2nd detection signal initializes the 2nd sequential circuit 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric circuit which uses both an external power supply installed outside and an internal power supply created internally using the external power supply as a power source. The present invention relates to a reduction in startup time of an internal power supply and a reduction in recovery time when a voltage drops.

[0002]

2. Description of the Related Art FIG. 17 shows an electric circuit provided with a sequential circuit which uses both an external power supply and an internal power supply as power sources and holds information. In the figure, reference numeral 1 denotes a first sequential circuit that holds information by an external power supply, 2 denotes a second sequential circuit that holds information by an internal power supply, and 3 denotes information held by the first and second sequential circuits 1 and 2. It is a combinational circuit that performs operations. These electric circuits output operation results corresponding to the external power state and the internal power state, such as the external power voltage value and the internal power voltage value.

Usually, a plurality of such electric circuits are connected in parallel to perform multi-bit addition / subtraction processing (however,
The addition / subtraction processing circuit is not shown). Such sequential circuits of an electric circuit that performs addition and subtraction processing with a plurality of power supplies need to be properly initialized when the power is turned on and after the power supply voltage drops. For example, when the information held in the first sequential circuit 1 is initialized, the information held in the second sequential circuit 2 needs to be initialized at the same time, and the initialization signal (ZPOR) of the first sequential circuit 1 must be initialized. ) And an initialization signal (Z
VCC2POR).

[0004] As an initialization signal of each conventional sequential circuit, for example, an example is considered in which the initialization signal of the first sequential circuit is used as it is as the initialization signal of the second sequential circuit and is linked. In this case, the initialization of the circuit using the external power supply as the power source is performed by the initialization signal (ZPOR) according to the change of the external power supply.
When is output, there is no problem because it is appropriately changed and handled.

However, this initialization signal (ZPOR)
Since it is unrelated to the internal power supply, the initialization signal (ZPO
R), the initialization signal (ZVCC2PO)
R) is output to initialize the circuit using the internal power source as a power source. After that, if the internal power source needs to be started, the problem that the circuit using the internal power source as a power source has not been initialized is caused. Occurs.

[0006] As a method for eliminating the delay in starting the internal power supply, there is a method in which the supply capability of the voltage step-down circuit is set to be large from the beginning. However, this countermeasure has a problem that charging and discharging within the allowable value of the current consumption of the entire electric circuit is delayed, and an abnormal increase in the internal power supply due to overcharging is likely to occur.

Each initialization signal of each of the other conventional sequential circuits is
For example, a detection circuit that outputs an initialization signal (ZPOR) when the voltage of the external power supply drops below a predetermined value;
There is a method of separately forming a detection circuit that outputs an initialization signal (ZVCC2POR) when the voltage of the internal power supply falls to a predetermined value or less, and performing the detection circuit separately.

In this case, when the external power supply falls below a predetermined value due to disturbance outside the electric circuit, an initialization signal (ZPOR) is output, and initialization of the sequential circuit using the external power supply as a power source is performed. . However, even if the external power supply drops below the predetermined value, the internal power supply does not instantaneously drop below the predetermined value, and it takes some time. Therefore, it takes some time before the initialization signal (ZVCC2POR) is output.

[0009]

A conventional electric circuit is constructed as described above, and in the case of an electric circuit operated by a plurality of power supplies, a circuit operated by each power supply, in particular, an order of holding information by an internal power supply. There has been a problem that the circuit has not been properly initialized. In addition, there is a problem that it takes time to recover after an instantaneous voltage drop of the internal power supply due to the initialization.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to appropriately initialize a sequential circuit for retaining information by an internal power supply, thereby shortening a time required for recovery from a voltage drop. It is an object of the present invention to provide an electric circuit capable of performing the above.

[0011]

Means for Solving the Problems Claim 1 according to the present invention.
The electric circuit of the second voltage source created by stepping down in a voltage step-down circuit connected to a first voltage source provided outside, the step-down voltage of the first voltage source as a power source Each voltage including a reference voltage creating circuit that creates a reference voltage as an index, a first sequential circuit that holds information with a first voltage source, and a second sequential circuit that holds information with a second voltage source A main circuit using the power source as a power source, and using the first voltage source or the second voltage source as a power source, detecting that the voltage of the first voltage source is smaller than a predetermined value, and generating a first detection signal. The first detection circuit to output, the first voltage source as a power source, a circuit including a third sequential circuit, the difference between the reference voltage and the voltage of the second voltage source is greater than a predetermined value and When the initialization of the third sequential circuit is performed by the logical sum with the first detection signal, the second detection signal is output. An electrical circuit that includes a second detection circuit that, the second detection signals, and performs initialization of the second sequence circuit.

Further, the electric circuit according to claim 2 of the present invention comprises a second voltage source which is created by stepping down a voltage by a voltage step-down circuit connected to a first voltage source provided outside; A reference voltage creation circuit that creates a reference voltage as an index of a step-down voltage using the first voltage source as a power source, and a main circuit that uses two power sources, a first voltage source and a second voltage source, as power sources, A first detection circuit that detects that the voltage of the first voltage source is smaller than a predetermined value and outputs a first detection signal, using the first voltage source or the second voltage source as a power source, A circuit including a third sequential circuit using the one voltage source as a power source, and a logical sum of a difference between a reference voltage and a voltage of the second voltage source being larger than a predetermined value and a first detection signal; And a second detection circuit that outputs a second detection signal when the initialization of the third sequential circuit is performed. An electrical circuit, the second detection signal, and increases the operating current of the voltage step-down circuit.

According to a third aspect of the present invention, there is provided the electric circuit according to the third aspect, wherein the second voltage is generated by stepping down the voltage by a first voltage step-down circuit connected to a first voltage source provided outside. Source, a third voltage source created by stepping down in a second voltage step-down circuit connected to the first voltage source, and a reference voltage as an index of the step-down voltage using the first voltage source as a power source A reference voltage generating circuit, a first sequential circuit that holds information in a first voltage source, a second sequential circuit that holds information in a second voltage source, and information in a third voltage source. And a fourth sequential circuit that holds a main circuit that uses three power sources of each voltage source as a power source, and a second voltage source that is a power source, and the voltage of the second voltage source is smaller than a predetermined value. And a fourth detection circuit that outputs a fourth detection signal and a third sequential circuit using the first voltage source as a power source. When the difference between the reference voltage and the voltage of the third voltage source is larger than a predetermined value, and the third sequential circuit is initialized by the logical sum of the fourth detection signal and And a fifth detection circuit that outputs a fifth detection signal, the fifth detection signal,
The fourth sequential circuit is initialized.

According to a fourth aspect of the present invention, there is provided an electric circuit, comprising: a second voltage stepped down by a first voltage step-down circuit connected to a first voltage source provided outside. Source, a third voltage source created by stepping down in a second voltage step-down circuit connected to the first voltage source, and a reference voltage as an index of the step-down voltage using the first voltage source as a power source A reference voltage generating circuit, a main circuit using three power sources of a first voltage source, a second voltage source, and a third voltage source as power sources, and a second voltage source as a power source, A fourth detection circuit that detects that the voltage of the voltage source is smaller than a predetermined value, and outputs a fourth detection signal, and uses the first voltage source as a power source and a circuit including a third sequential circuit. The difference between the reference voltage and the voltage of the third voltage source is larger than a predetermined value, and the logical sum of the fourth detection signal and When the initialization of the sequential circuit is performed in,
An electric circuit comprising: a fifth detection circuit that outputs a fifth detection signal, wherein the fifth detection signal increases an operating current of the second voltage step-down circuit.

According to a fifth aspect of the present invention, there is provided an electric circuit comprising: a reference voltage generating circuit for generating a reference voltage as an index of a step-down voltage by using a first voltage source provided externally as a power source; Amplifying circuit for current amplifying a voltage, a main circuit using the first voltage source and the amplifying circuit as a power source, and using the first voltage source as a power source, the voltage of the first voltage source is smaller than a predetermined value. A first detection circuit for detecting the first detection signal, and a circuit including a third sequential circuit using the first voltage source as a power source. A third detection circuit that outputs a third detection signal when the difference is larger than a predetermined value and the third sequential circuit is initialized by a logical sum of the first detection signal and the third detection circuit; An electric circuit that increases the operating current of the amplifier circuit by a third detection signal. It is.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described. FIG. 1 is a block diagram showing a configuration of an electric circuit according to Embodiment 1 of the present invention, and FIG.
Power-on reset circuit (ZPOR)
FIG. 3 is a circuit diagram showing a reference voltage generating circuit (VREF circuit) of the electric circuit shown in FIG. 1, and FIG. 4 is an analog circuit as an amplifier circuit of the electric circuit shown in FIG. FIG. 3 is a circuit diagram illustrating a buffer circuit (VREFBUF circuit).

FIG. 5 is a circuit diagram showing a standby voltage step-down circuit (STANDBY_VDC circuit) of the electric circuit shown in FIG. 1, and FIG. 6 is a circuit diagram showing a second or third detection circuit (ALIVE circuit) of the electric circuit shown in FIG. FIG. 7 is an active voltage step-down circuit (A) of the electric circuit shown in FIG.
CTIVE_VDC circuit), and FIG.
FIG. 2 is a circuit diagram showing a buffer circuit (ZVCC2POR circuit) of the electric circuit shown in FIG.

FIG. 9 is a circuit diagram showing a reference voltage load circuit (LOADDLINE circuit) of the electric circuit shown in FIG. 1, and FIG. 10 is a load circuit (L) of an internal power supply of the electric circuit shown in FIG.
FIG. 11 is a main circuit of an electric circuit, which is driven by an external power supply provided as an external first power supply and an internal power supply serving as a second voltage supply described later. It is.

In FIG. 1, reference numeral 4 denotes a first detection signal (ZPOR) when the external power supply (VCC) or the internal power supply (VCC2) is used as a power source and the voltage (VCC) of the external power supply is detected to be smaller than a predetermined value. In the power-on reset circuit (ZPOR circuit) as a first detection circuit, the first detection signal (ZPOR) is used to initialize a first sequential circuit 21 (FIG. 11) using an external power source as a power source, which will be described later. Also functions as an initialization signal for performing

A reference voltage generating circuit (VR) 5 generates a reference voltage as an index of a step-down voltage using an external power supply as a power source.
An EF circuit 6 is a buffer circuit (VREFBUF circuit) as an amplifier circuit for amplifying the current of the reference voltage, and increases an operating current when a third detection signal (VREFALIVE) described later is input.

Reference numeral 7 denotes a standby voltage step-down circuit (STANDBY_VDC circuit) for stepping down a reference voltage, which is formed so as to be used as a part of the internal power supply in order to eliminate a delay in starting the internal power supply. 8 is an active voltage step-down circuit (ACTIVE_VD) connected to an external power supply.
Circuit C), the external power supply is stepped down to create an internal power supply as a second voltage source. When a second detection signal (VCC2ALIVE) described later is input, the operating current is increased.

9 is a reference voltage load circuit (LOADDLIN).
E circuit), 10 is a load circuit of the internal power supply (LOADADLIN)
E2 circuit), 11 is a second detection circuit composed of a circuit including a second sequential circuit 15 (FIG. 6) using an external power supply as a power source. The difference is larger than the predetermined value, and the first detection signal (ZP
When the initialization of the second sequential circuit 15 is performed by the logical OR with the OR, a second detection signal (VCC2ALIVE) is output.

Reference numeral 12 denotes a third detection circuit comprising a circuit including a third sequential circuit 15 (FIG. 6) using an external power source as a power source, and a reference voltage (VREF0) and a voltage (VRE0) of an amplifier circuit.
F_NEAR) is larger than a predetermined value, and the third sequential circuit 15 is initialized by the logical sum of the first detection signal (ZPOR) of the power-on reset circuit 4 and the third detection. A signal (VREFALIVE) is output.

A buffer circuit (ZVCC2POR circuit) 13 receives a second detection signal (VCC2ALIVE) and uses an internal power source as a power source to initialize a second sequential circuit 22 (FIG. 11) described later. Signal (ZVCC2
POR) is output. Reference numeral 21 denotes a first sequential circuit that retains information by an external power supply, 22 denotes a second sequential circuit that retains information by an internal power supply, and 23 denotes a combinational circuit that calculates information retained in both the sequential circuits 21 and 22. These electric circuits output operation results corresponding to the external power state and the internal power state, such as the external power voltage value and the internal power voltage value.

Usually, a plurality of such components as shown in FIG. 11 are connected in parallel to perform multi-bit addition / subtraction processing (however, an addition / subtraction processing circuit is not shown). Although the addition and subtraction processing is performed by a plurality of power supplies, the operation of each sequential circuit needs to be properly initialized when the power is turned on and after the power supply voltage drops.

Next, the first embodiment configured as described above
The operation of the electric circuit will be described. First, when the external power supply (VCC) is usually, for example, about 2.5 V, but falls below a predetermined value (for example, 1.1 V, which varies depending on the temperature state of the electric circuit), the power-on reset circuit (ZPOR) Changes from the normal “H” state to the “L” state, and the first detection signal (ZPOR) is output.

Then, as shown in FIG. 6, the second detection circuit 11 receives the first detection signal (ZPOR), and outputs the reference voltage (VREF_FAR) and the internal power supply voltage (VC
C2_NEAR), the third sequential circuit 15 is initialized, and the second detection signal (VCC2AL) is inverted.
IVE) is output.

Therefore, even when the voltage drops before the internal power supply voltage (VCC2) drops to the ground (GND) potential,
Through the buffer circuit 13, an initialization signal (ZVCC2POR) for initializing the second sequential circuit 22 that holds information with the internal power supply is output, and the second sequential circuit 22
Is initialized.

The second detection signal (VCC2ALIV)
E) is input to the voltage drop circuit 8. Then, the voltage drop circuit 8 increases the operating current and consumes the comparator current separately from the one caused by the normal circuit activation signal (ACT), thereby discharging the gate capacitance of the pMOS driver of the voltage drop circuit 8, The startup time of the load circuit 10 of the internal power supply shown in FIG.

As shown in FIG. 6, the third detection circuit 12 receives the first detection signal (ZPOR), and outputs a reference voltage (VRE0) and an amplification circuit voltage (VREF_NE).
AR) is inverted, the third sequential circuit 15 is initialized, and a third detection signal (VREFALIVE) is output. Then, the third detection signal (VREFA
LIVE) is input to the amplifier circuit 6, the operating current increases (LARGE ICC), the driving current is improved by increasing the comparator current, and the reference voltage load circuit 9
To reduce startup time.

In the electric circuit according to the first embodiment configured as described above, the second sequential circuit holding information by the internal power supply of the electric circuit is immediately initialized even if there is a momentary voltage drop, Since driving is performed, recovery after a voltage drop can be performed in a short time. Furthermore, when the voltage drops, the operating currents of the voltage drop circuit and the internal power supply are increased, so that the start-up time of the load circuit can be shortened.

Embodiment 2 FIG. FIG. 12 is a block diagram showing a configuration of an electric circuit according to Embodiment 2 of the present invention, and FIG. 13 is a power-on reset circuit (ZP) of the electric circuit shown in FIG.
FIG. 14 is a circuit diagram showing an OR_A circuit, and FIG. 14 is a level shifter circuit (LEVEL_SHIF) of the electric circuit shown in FIG.
T circuit), FIG. 15 is a circuit diagram showing a buffer circuit (ZVCC3POR circuit) of the electric circuit shown in FIG. 12, and FIG. 16 is a reference voltage generating circuit of the electric circuit shown in FIG. It is a circuit diagram.

Although not shown, similarly to the first embodiment, the electric circuit includes an external power supply as a first voltage source, a first internal power supply as a second voltage source, and
A first sequential circuit for holding information by an external power supply, and a second circuit for holding information by a first internal power supply, including a main circuit powered by three power supplies of a second internal power supply as a third voltage source. And a fourth sequential circuit that retains information with a second internal power supply.

In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description is omitted. Reference numeral 30 designates the voltage (VCC) of the first internal power
2) is smaller than a predetermined value, a power-on reset circuit (ZPOR_A circuit) that outputs a fourth detection signal (ZPOR2), and a fourth detection signal (ZPOR_A).
R2) is a fourth detection circuit including a level shifter circuit (LEVEL_SHIFT circuit) that performs voltage amplitude conversion so as to become an initialization signal (ZPOR) of a second sequential circuit that holds information by a first internal power supply. . However, here, the initialization signal (ZPOR) is used as the fourth detection signal.

Reference numeral 31 denotes a reference voltage (VREF0 and VREF1) as an index of a step-down voltage using an external power source as a power source.
Is a reference voltage generation circuit (VREF_A circuit)
The reference voltage (VREF0) is set to a voltage higher than the reference voltage (VREF1). 32 is a reference voltage (VRE
Amplifying circuit (VREFBUF circuit) for current amplifying F0)
When the third detection signal (VREF1ALIVE) is input, the operating current is increased.

Reference numeral 33 denotes a standby voltage step-down circuit (STANDBY_VDC circuit) for stepping down the reference voltage (VREF1), which is formed so as to be used as a part of the internal power supply in order to eliminate a start-up delay of the internal power supply. .
Reference numeral 34 denotes an active second voltage step-down circuit (ACTIVE_VDC circuit) connected to an external power supply, which steps down the external power supply to create a second internal power supply as a third voltage source. When the fifth detection signal (VCC3ALIVE) is input, the operating current is increased.

35 is a load circuit (LOADDLINE circuit) for the reference voltage (VREF1), 36 is a load circuit for the second internal power supply (LOADDLINE2 circuit), and 37 is a circuit using an external power supply as a power source and including a third sequential circuit. A difference between the reference voltage (VREF1_FAR) and the voltage of the second internal power supply (VCC3_NEAR) is larger than a predetermined value, and the fourth detection signal (ZPOR) of the fourth detection circuit 30 ), The third detection circuit (VCC3ALIV) is initialized.
E) is output.

Reference numeral 38 denotes a third detection circuit comprising a circuit including a third sequential circuit using an external power supply as a power source, and a reference voltage (VREF1) and a voltage of the amplifier circuit (VREF1_NEA).
R) is smaller than a predetermined value, and the third sequential circuit is initialized by the logical sum of the fourth detection signal (ZPOR) of the fourth detection circuit 30 and the third detection. A signal (VREF1ALIVE) is output.

Reference numeral 39 denotes a buffer circuit (ZVCC2POR circuit) which receives a fifth detection signal (VCC3ALIVE) and initializes a fourth sequential circuit which holds information with a second internal power supply (ZVCC3POR circuit). ) Is output.

Next, the second embodiment configured as described above
The operation of the electric circuit will be described. First, when the first internal power supply (VCC2) is usually about 2.5 V, for example, but drops below a predetermined value (for example, 1.1 V, which varies depending on the temperature state of the electric circuit), the fourth detection is performed. Circuit (Z
POR) 30 changes from the normal "H" state to the "L" state, and the fourth detection signal (ZPOR) is output.

Then, the fifth detection circuit 37 is configured in the same manner as in FIG. 6 of the first embodiment, receives the fourth detection signal (ZPOR), and receives the reference voltage (VREF1_FA).
R) and the second internal power supply voltage (VCC3_NEAR)
Are inverted, the third sequential circuit is initialized, and the fifth detection signal (VCC5ALIVE) is output.

Therefore, the second internal power supply voltage (VCC3)
Signal through a buffer circuit 39 to initialize a fourth sequential circuit for retaining information with a second internal power supply even at the time of voltage drop before the voltage drops to the ground (GND) potential. ) Is output, and the fourth sequential circuit is initialized.

The fifth detection signal (VCC3ALIV)
E) is input to the second voltage drop circuit 34. And
In the second voltage drop circuit 34 (configured in the same manner as in FIG. 7 of the first embodiment), the operating current is increased, and the comparator current is consumed separately from the normal circuit activation signal (ACT). Thereby, the gate capacitance of the pMOS driver of the second voltage drop circuit 34 is discharged, and the rise time of the load circuit 36 of the second internal power supply is shortened.

The third detection circuits 12 and 38 receive the fourth detection signal (ZPOR) and receive the reference voltage (VR).
EF0, VREF1) and the amplifier circuit voltage (VREF_
The latch in NEAR, VREF1_NEAR) is inverted, the third sequential circuit is initialized, and the third detection signal (VREFALIVE, VREF1ALIVE) is output. Then, the third detection signal (VREFALI)
VE, VREF1ALIVE) are input to the amplifier circuits 6, 32, the operating current is increased, and the drive current is improved by increasing the comparator current, and the rise time of the reference voltage load circuits 9, 35 is shortened. .

In the electric circuit according to the second embodiment configured as described above, the fourth sequential circuit that holds information by the second internal power supply of the electric circuit is immediately initialized even in the case of a momentary voltage drop. , The recovery after the voltage drop can be performed in a short time. Furthermore, at the time of voltage drop, the operating current of the voltage drop circuit and the internal power supply increases,
The startup time of the load circuit can be reduced.

[0046]

As described above, according to the first aspect of the present invention, the second voltage generated by stepping down the voltage by the voltage step-down circuit connected to the externally provided first voltage source. Source
A reference voltage creating circuit that creates a reference voltage as an index of a step-down voltage using the first voltage source as a power source, a first sequential circuit that holds information by the first voltage source, and information by the second voltage source. A main circuit including a second sequential circuit for holding and using each voltage source as a power source; and using the first voltage source or the second voltage source as a power source, the voltage of the first voltage source is lower than a predetermined value. A first detection circuit that detects that it is small and outputs a first detection signal, the first voltage source as a power source, a circuit including a third sequential circuit, a reference voltage and a second voltage source The second detection circuit that outputs the second detection signal when the difference between the third detection circuit and the first detection signal is larger than the predetermined value and the third sequential circuit is initialized by the logical sum with the first detection signal. Since the initialization of the second sequential circuit is performed by the second detection signal, the second circuit Before pressure source is fully buck, it is possible to provide an electrical circuit that can perform recovery of the second voltage source.

Further, according to the second aspect of the present invention, the second voltage source formed by stepping down the voltage by the voltage step-down circuit connected to the externally provided first voltage source, A reference voltage generating circuit for generating a reference voltage as an index of a step-down voltage using the voltage source as a power source; a main circuit using two power sources, a first voltage source and a second voltage source; A first detection circuit that detects that the voltage of the first voltage source is smaller than a predetermined value and outputs a first detection signal, using the voltage source or the second voltage source as a power source, A voltage source is used as a power source, and a circuit including a third sequential circuit is provided.The difference between the reference voltage and the voltage of the second voltage source is greater than a predetermined value, and the logical sum of the first detection signal and the difference is provided. When the initialization of the third sequential circuit is performed, an electric circuit including a second detection circuit that outputs a second detection signal is provided. A is, the second detection signal,
Since the operating current of the voltage step-down circuit is increased, it is possible to provide an electric circuit capable of shortening the recovery time of the second voltage source.

Further, according to the third aspect of the present invention, the second voltage source formed by stepping down by the first voltage step-down circuit connected to the externally provided first voltage source is provided. A third voltage source created by stepping down with a second voltage step-down circuit connected to the first voltage source, and a reference voltage as an index of the step-down voltage using the first voltage source as a power source. A reference voltage generating circuit, a first sequential circuit that holds information in a first voltage source, a second sequential circuit that holds information in a second voltage source, and holds information in a third voltage source. And a main circuit powered by three power sources of each voltage source, and a power source powered by the second voltage source, wherein the voltage of the second voltage source is smaller than a predetermined value. A fourth detection circuit that detects and outputs a fourth detection signal, and includes a third sequential circuit using the first voltage source as a power source When the difference between the reference voltage and the voltage of the third voltage source is larger than a predetermined value and the initialization of the third sequential circuit is performed by the logical sum of the fourth detection signal, And a fifth detection circuit that outputs a fifth detection signal, wherein the fifth detection signal initializes the fourth sequential circuit, so that the third voltage source is completely stepped down. It is possible to provide an electric circuit capable of performing the recovery of the third voltage source before the operation.

Further, according to the fourth aspect of the present invention, the second voltage source formed by stepping down the voltage by the first voltage step-down circuit connected to the externally provided first voltage source is provided. A third voltage source created by stepping down with a second voltage step-down circuit connected to the first voltage source, and a reference voltage as an index of the step-down voltage using the first voltage source as a power source. A reference voltage generating circuit, a main circuit powered by three power sources, a first voltage source, a second voltage source, and a third voltage source, and a second voltage source powered by the second voltage source. A fourth detection circuit that detects that the voltage of the source is smaller than a predetermined value and outputs a fourth detection signal, and includes a circuit including a third sequential circuit, using the first voltage source as a power source, The difference between the reference voltage and the voltage of the third voltage source is greater than a predetermined value, and the third order is determined by the logical sum of the fourth detection signal and the fourth detection signal. An electric circuit including a fifth detection circuit that outputs a fifth detection signal when the initialization of the path is performed, and the operating current of the second voltage step-down circuit is increased by the fifth detection signal. Therefore, it is possible to provide an electric circuit capable of shortening the recovery time of the third voltage source.

According to a fifth aspect of the present invention, a reference voltage generating circuit for generating a reference voltage as an index of a step-down voltage by using a first voltage source provided externally as a power source, Amplifying circuit for current amplification, a main circuit using the first voltage source and the amplifying circuit as a power source, and using the first voltage source as a power source, the voltage of the first voltage source being smaller than a predetermined value. A first detection circuit for detecting and outputting a first detection signal, and a circuit including a third sequential circuit using the first voltage source as a power source, wherein a difference between the reference voltage and the voltage of the amplifier circuit is obtained. An electric circuit including a third detection circuit that outputs a third detection signal when initialization of the third sequential circuit is performed by a logical sum of the first detection signal and a third detection circuit that is greater than the predetermined value; Since the operating current of the amplifier circuit is increased by the third detection signal, It is possible to provide an electrical circuit that can shorten the time of recovery of the road.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electric circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a power-on reset circuit (ZPOR circuit) of the electric circuit shown in FIG.

FIG. 3 is a circuit diagram showing a reference voltage generation circuit (VREF circuit) of the electric circuit shown in FIG.

4 is a circuit diagram showing an analog buffer circuit (VREFBUF circuit) as an amplifier circuit of the electric circuit shown in FIG.

FIG. 5 is a circuit diagram showing a standby voltage step-down circuit (STANDBY_VDC circuit) of the electric circuit shown in FIG. 1;

FIG. 6 is a circuit diagram showing a second or third detection circuit (ALIVE circuit) of the electric circuit shown in FIG. 1;

FIG. 7 is a circuit diagram showing an active voltage step-down circuit (ACTIVE_VDC circuit) of the electric circuit shown in FIG. 1;

FIG. 8 shows a buffer circuit (ZV) of the electric circuit shown in FIG.
FIG. 3 is a circuit diagram illustrating a CC2POR circuit).

FIG. 9 shows a reference voltage load (L) of the electric circuit shown in FIG. 1;
FIG. 2 is a circuit diagram illustrating an OADLINE circuit).

10 is a circuit diagram showing a load (LOADDLINE2 circuit) of an internal power supply of the electric circuit shown in FIG. 1;

FIG. 11 is a main circuit of the electric circuit shown in FIG. 1;

FIG. 12 is a block diagram showing an electric circuit according to a second embodiment of the present invention.

13 is a circuit diagram showing a power-on reset circuit (ZPOR circuit) of the electric circuit shown in FIG.

14 is a circuit diagram showing a level shifter circuit (LEVEL_SHIFT circuit) of the electric circuit shown in FIG.

15 is a circuit diagram showing a buffer circuit (ZVCC3POR circuit) of the electric circuit shown in FIG.

FIG. 16 is a circuit diagram showing a reference voltage generation circuit of the electric circuit shown in FIG.

FIG. 17 is a main circuit of a conventional electric circuit.

[Explanation of symbols]

4 power-on reset circuit, 5, 31 reference voltage generating circuit, 6 amplifying circuit, 7, 33 standby voltage step-down circuit, 8 voltage step-down circuit, 9, 10, 35, 36 load circuit, 11 second detection circuit, 12, 38 third detection circuit, 13, 32, 39 buffer circuit, 15 third sequence circuit, 21 first sequence circuit, 22 second sequence circuit, 23 combination circuit, 30 fourth detection circuit, 3
4 Second voltage step-down circuit, 37 Fifth detection circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (5)

[Claims] 1. A second voltage source which is created by stepping down a voltage by a voltage step-down circuit connected to a first voltage source provided outside, and a step-down voltage using the first voltage source as a power source. A reference voltage generation circuit that generates a reference voltage as an index of, a first sequential circuit that holds information in the first voltage source and a second sequential circuit that holds information in the second voltage source A main circuit including the respective voltage sources as power sources, and detecting that the voltage of the first voltage source is smaller than a predetermined value, using the first voltage source or the second voltage source as a power source. A first detection circuit that outputs a first detection signal, and a circuit including a third sequential circuit, using the first voltage source as a power source, the reference voltage and the voltage of the second voltage source. Is larger than a predetermined value, and the third order is obtained by ORing with the first detection signal. When the initialization of the circuit is performed, it is an electric circuit including a second detection circuit that outputs a second detection signal, the initialization of the second sequential circuit by the second detection signal An electric circuit characterized by performing. 2. A second voltage source, which is created by stepping down a voltage by a voltage step-down circuit connected to a first voltage source provided outside, and a step-down voltage using the first voltage source as a power source. A reference voltage generation circuit that generates a reference voltage as an index of the main voltage, a main circuit that uses two power sources, the first voltage source and the second voltage source, as a power source, and the first voltage source or the second voltage source. Using the second voltage source as a power source, a first detection circuit that detects that the voltage of the first voltage source is smaller than a predetermined value and outputs a first detection signal, and the first voltage source As a power source,
A circuit including a third sequential circuit, wherein the difference between the reference voltage and the voltage of the second voltage source is larger than a predetermined value, and the third logical sum of the third detection signal and the first detection signal. An electric circuit including a second detection circuit that outputs a second detection signal when initialization of the sequential circuit is performed, and the operating current of the voltage step-down circuit is increased by the second detection signal. An electric circuit characterized by causing the electric circuit to: 3. A second voltage source produced by stepping down a voltage by a first voltage step-down circuit connected to a first voltage source provided outside, and connected to the first voltage source. A third voltage source created by stepping down in the second voltage step-down circuit, a reference voltage creation circuit that creates a reference voltage as an index of the step-down voltage using the first voltage source as a power source, A first sequential circuit that retains information at the first voltage source, a second sequential circuit that retains information at the second voltage source, and a fourth sequence that retains information at the third voltage source And a main circuit that uses three power sources of the respective voltage sources as power sources, and uses the second voltage source as a power source to detect that the voltage of the second voltage source is smaller than a predetermined value. A fourth detection circuit that outputs a fourth detection signal, and the first voltage source as a power source,
A circuit including a third sequential circuit, wherein the difference between the reference voltage and the voltage of the third voltage source is larger than a predetermined value, and the third logical sum of the fourth detection signal and the third When the initialization of the sequential circuit is performed, an electric circuit including a fifth detection circuit that outputs a fifth detection signal, wherein the fifth detection signal initializes the fourth sequential circuit. An electric circuit characterized by performing: 4. A second voltage source produced by stepping down a voltage by a first voltage step-down circuit connected to a first voltage source provided outside, and connected to the first voltage source. A third voltage source created by stepping down in the second voltage step-down circuit, a reference voltage creation circuit that creates a reference voltage as an index of the step-down voltage using the first voltage source as a power source, A main circuit that uses three power sources of a first voltage source, the second voltage source, and the third voltage source as a power source, and a voltage of the second voltage source that uses the second voltage source as a power source. A fourth detection circuit that detects that is smaller than a predetermined value, and outputs a fourth detection signal; and a circuit including a third sequential circuit, using the first voltage source as a power source, and The difference between the voltage and the voltage of the third voltage source is greater than a predetermined value, and the logical sum of the fourth detection signal and When the initialization of the third sequential circuit is performed, an electric circuit including a fifth detection circuit that outputs a fifth detection signal, the fifth detection signal, the second voltage An electric circuit characterized by increasing an operation current of a step-down circuit. 5. A reference voltage generating circuit for generating a reference voltage as an index of a step-down voltage using a first voltage source provided externally as a power source, an amplifying circuit for current amplifying the reference voltage, A main circuit using the one voltage source and the amplifier circuit as a power source, and using the first voltage source as a power source, detecting that the voltage of the first voltage source is smaller than a predetermined value, And a circuit including a third sequential circuit using the first voltage source as a power source, wherein a difference between the reference voltage and the voltage of the amplifier circuit is a predetermined value. An electric circuit comprising a third detection circuit that outputs a third detection signal when the third sequential circuit is initialized by a logical sum of the first detection signal and the third detection circuit. The operating current of the amplifier circuit is increased by the third detection signal. An electric circuit characterized by causing