JP2000023481A - Pwm control circuit apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize highly accurate and stable anti-jitter characteristic of a PWM control circuit apparatus, by providing in it switching elements for outputting therefrom the control signals of a motor through inputting thereinto the control signals fed from the control circuit of its output elements. SOLUTION: This apparatus has a reset circuit formed out of an NPN transistor 121 connected in parallel with a capacitor C1 and has a triangular-wave reset circuit 103. Such a triangular-wave signal S11 can be generated from a triangular-wave generating circuit 102 that when performing the ON/OFF control of the NPN transistor 121, L-side switching elements 114-116 are changed over and every timing of the changeover thereof, the capacitor C1 is forcedly discharged and repeatedly charged. Also, synchronizing this triangular-wave signal S11 with an output signal S12 generated based on phase signals S7-S9, the ON and OFF times of a PWM signal S13 are made to coincide with each other to make also possible the coincidence of its ON timing with its OFF timing. Thereby, the highly accurate and stable anti-jitter characteristic of this apparatus can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for driving a controlled device (polyphase motor) by a PWM control method, and controls a triangular wave carrier signal serving as a reference of control timing and a rotation speed of the polyphase motor. The present invention relates to a PWM control circuit device that reduces fluctuations in the rotational speed of a polyphase motor with a control signal and stabilizes the PWM control circuit with high accuracy.

[0002]

2. Description of the Related Art In recent OA equipment such as printers, copiers and fax machines, a polyphase motor is used as a drive source for a photosensitive drum and other mechanically driven parts. Of these OA devices, most of those that are sold as high-end machines are those that employ a laser system with high print quality. A scanner motor (polyphase motor) for laser scanning built in these high-grade OA devices is driven at a high rotation speed of 5,000 to tens of thousands of rotations per minute. For this reason, high precision is required for motor speed control, and some motors require a rotation unevenness characteristic of 0.01% or less. In recent years, in addition to the increase in the rotation speed of motors, the demand for miniaturization (miniaturization of design patterns) of semiconductor integrated circuit devices has increased, and it is necessary to realize high withstand voltage and large current of ICs. Has occurred. In order to cope with the high withstand voltage, the structure of a portion to which a high voltage is applied has been strengthened. Further, in order to cope with an increase in current, a structure for reducing power consumption in an IC and a speed control method of a motor are characterized. Here, the motor speed control method is roughly divided into a current control method and a voltage control method. For increasing the current, voltage control with less power consumption of the IC is more convenient. The speed control method is adopted.

[0003] From the viewpoint of increasing the current, a PWM control method is adopted as a motor drive control method. However, in order to obtain high accuracy by the PWM control method, various contrivances are required. is there. That is, by inputting a highly accurate control signal (external clock) from the outside, the PWM
The method of synchronizing the output frequency is adopted. For example, (1) an accurate reference clock signal is externally supplied, a signal obtained by dividing the reference clock signal is used as a PWM carrier signal, (2) a method of synchronizing the frequency of the PWM carrier signal and the rotation angle frequency of the motor with a PLL control circuit, (3) a rotation speed of the motor , And a method of synchronizing by applying feedback to an oscillator that generates a PWM carrier frequency. In that case, a special circuit must be provided. Although such a circuit has high accuracy, it has a large circuit scale. In particular
When the feedback circuit is provided as in (3), another problem that the control signal easily oscillates occurs. In the present invention described later, high-precision control is realized by medium-precision hardware having a small circuit scale without providing such high-precision and large-scale hardware.

When a multi-phase motor is driven by PWM control, PWM which is a reference frequency of motor control timing is used.
It is desirable to configure the M carrier frequency and the rotation angle frequency of the motor in an integer ratio. However, if the integer ratio is not taken, the speed control of the polyphase motor will be slightly different in each phase, and this will appear as variation in the rotation speed. As the causes, for example, (1) a driving time deviation in which a time during which one phase is ON (active) and accelerating is different from a time when another phase is ON and accelerating, (2) Even if each phase is ON for the same time, a cause may occur due to a deviation in the driving period such that one phase drives the first period of the phase section and another phase drives the last period of the phase section. Then, it is not possible to realize a further high-precision motor control required by the times. In particular, high-precision rotation unevenness characteristics (0.0, such as a laser motor for a scanner motor, etc.)
When the PWM control method is applied to a system requiring (1% or less), the influence of this deviation appears remarkably in the rotation unevenness characteristic.

FIG. 9 is a diagram showing an example of a simplified conventional PWM control circuit. Here, a case in which a three-phase spindle motor M (hereinafter, referred to as a motor M) is driven as a polyphase motor will be described. 100 is a PWM control circuit device. A speed control circuit 101 outputs a control reference voltage signal S12. This control reference voltage signal S12 is
It is input from the external terminal VCTL of the WM control circuit device 100. Reference numeral 102 denotes a triangular wave generation circuit, which is a constant current source that generates a constant current. C1 is a capacitor provided between the triangular wave generation circuit 102 and the ground potential. The triangular-wave generating circuit 102 outputs a triangular-wave signal S11 serving as a PWM control carrier signal by supplying a constant current in the charging direction and the discharging direction of the capacitor C1. The capacity of the capacitor C1 is appropriately set according to the rotation speed range of the motor M. A comparator 106 receives and compares the triangular wave signal S11 and the control reference voltage signal S12 input from the terminal VCTL, and outputs a PWM signal S13. H1-H3
Is a Hall element, which outputs position signals S1 to S6 according to the rotation angle of the motor M. R2 and R3 are limiting resistors for limiting the current flowing through the Hall elements H1 to H3. Reference numeral 104 denotes a position detection circuit, and the position signals S1 to S
6, and outputs phase signals S7 to S9 for determining which phase of the motor M should be supplied with current. An output element control circuit 105 includes phase signals S7 to S9 and a PWM signal S
13 and outputs switching element control signals G1 to G6. Switching elements 111 to 113 have their sources connected to the power supply Vcc, and switching element control signals G1 to G3 are input to the gates of the switching elements 111 to 113. 114 to 116 are switching elements whose drains are connected to the RS terminals, the sources of which are connected to the drains of the switching elements 111 to 113, respectively, and the switching element control signals G4 to G
6 is input to the gates of the switching elements 114 to 116. The drains of the switching elements 111 to 113 are connected to external terminals OUT1 to OUT3, respectively, and perform excitation control of each phase of the motor M. A current detection resistor R1 is provided between the external terminal RS and the ground potential.

The operation of the conventional PWM control circuit shown in FIG. 9 will be described. The comparator 106 is connected to the speed control circuit 10
When the control reference voltage signal S12 from 1 is supplied, the control reference voltage signal S12 is compared with the triangular wave signal S11. When the condition of S11 <S12 is satisfied, a high level “Hi” is output as the PWM signal S13. This state is referred to as “PWM
In the “PWM ON” state, the PWM
The output element control circuit 105 to which “Hi” of the M signal S13 has been input receives one of the switching elements 111 to 113 and the switching element 1 based on the phase signals S7 to S9.
One of the switching element control signals G1 to G3 and one of the switching element control signals G4 to G6 are set to "Hi" so that one of the switching element control signals G1 to G6 is turned on.
Is output. However, switching elements 111 and 11
4, or 112 and 115, or 113 and 116, are not simultaneously "on" (so-called "through").

Conversely, when the condition of S11> S12 is satisfied, the comparator 106 outputs a low level "Low" as the PWM signal S13.
Is output. This state is referred to as a “PWM off” state.
In the “PWM off” state, the output element control circuit 105
Outputs switching element control signals G4 to G6 such that all of the switching elements 114 to 116 are turned off. Further, one of the switching elements 114 to 11 which has been turned “ON” immediately before the state of “PWM OFF” has been reached.
6 and the switching elements 111 to 11 connected to the source
3 are also turned on. That is, the output element control circuit 10
5 outputs switching element control signals G1 to G6 that simultaneously turn on two of the switching elements 111 to 113 and turn off all other switching elements. For example, immediately before the state of “PWM off”, OU
Assuming that the phase of T1 is active and the switching elements 111 and 115 are “ON”, the current path of the motor M is Vcc → switching element 111 → OUT1 terminal → motor M → OUT2 terminal → switching element 115 →
RS terminal → current detection resistor R1 → GND. When this becomes the “PWM off” state, the current path of the motor M is connected in a loop with the switching element 111 → OUT1 terminal → motor M → OUT2 terminal → switching element 112 → switching element 111, and flows through the motor M. The current will be regenerated. And OUT1
Is active and S11 <S12 again ("PWM ON" state), Vcc → switching element 111 → OUT1 terminal → motor M → OUT2 terminal → switching element 115 → RS terminal → current detection resistor R1 again
→ Current flows through the GND current path. In addition,
If the “PWM off” state continues, the current flowing in a loop is consumed by the self-loss of the motor M,
Gradually slows down and finally stops.

Here, the following six current paths are formed in the current path in the “PWM ON” state. OUT1 phase; (1) Vcc → switching element 111 → OUT1 terminal →
Motor M → OUT2 terminal → switching element 115 → R
S terminal → current detection resistor R1 → GND (2) Vcc → switching element 111 → OUT1 terminal →
Motor M → OUT3 terminal → Switching element 116 → R
S terminal → current detection resistor R1 → GND OUT2 phase; (3) Vcc → switching element 112 → OUT2 terminal →
Motor M → OUT3 terminal → Switching element 116 → R
S terminal → current detection resistor R1 → GND (4) Vcc → switching element 112 → OUT2 terminal →
Motor M → OUT1 terminal → Switching element 114 → R
S terminal → current detection resistor R1 → GND OUT3 phase; (5) Vcc → switching element 113 → OUT3 terminal →
Motor M → OUT1 terminal → Switching element 114 → R
S terminal → current detection resistor R1 → GND (6) Vcc → switching element 113 → OUT3 terminal →
Motor M → OUT2 terminal → switching element 115 → R
S terminal → Current detection resistor R1 → GND

In the current path in the "PWM off" state, the following six current paths are formed. OUT1 phase; (1 ′) switching element 111 → OUT1 terminal → motor M → OUT2 terminal → switching element 112 → switching element 111 (2 ′) switching element 111 → OUT1 terminal → motor M → OUT3 terminal → switching element 113 → switching (3 ′) Switching element 112 → OUT2 terminal → Motor M → OUT3 terminal → Switching element 113 → Switching element 112 (4 ′) Switching element 112 → OUT2 terminal → Motor M → OUT1 terminal → Switching element 111 → phase of switching element 112 OUT3; (5 ′) switching element 113 → OUT3 terminal → motor M → OUT1 terminal → switching element 111 → switching element 113 (6 ′) switching element 113 → OUT3 terminal → motor M → OUT Terminal → switching element 112 → switching element 113

In general, switching of such a current path is called "commutation". The regenerative current path in the “PWM off” state may form a loop with the switching elements 114 to 116. Current detection resistor R1
When the voltage VR1 generated on the motor M exceeds a certain value, the output element control circuit 105 controls the switching elements 111 to 116 so that no more current flows through the motor M. For example, the state may be set to “PWM off”. This control is required only when the motor M is started or when there is no load.
Since the control is M, the description is omitted. The current detecting resistor R1 is connected to the Vcc terminal and the switching elements 111 to 11.
3 may be provided between the three sources.

FIG. 10 is a signal waveform diagram (timing diagram) showing the operation of the conventional circuit. However, the motor M is operated at a constant rotation. Phase excitation voltage VOUT1
VOUT3 is a potential waveform at the OUT1 to OUT3 terminals, and transitions between Vcc, 1/2 Vcc, and GND. When the phase excitation voltage VOUT1 is Vcc, the phase of OUT1 is excited (the OUT1 phase is “active”). The phase signals S7 to S9 are position signals S1 indicating the rotation angle of the motor M.
This is an output signal from the position detection circuit 104 generated based on .about.S6, and it is possible to determine which phase is to be excited using this phase signal. For example, the phase of OUT1 is excited when a value obtained by ANDing / S7 (an inverted signal of the phase signal S7) and the phase signal S8 becomes “Hi”. When the control shown in FIG. 10 is performed, the motor M is driven from OUT1 → OUT2 → OUT3 → OU
It is rotating in the T1 direction.

The output element control circuit 105 is set to "PWM ON".
Signal and the PWM signal S13 for setting the state of “PWM off”
Is generated from the triangular wave signal S11 and the control reference voltage signal S12. Triangular wave signal S that repeats a constant cycle and amplitude
11, when the level is higher than the external control reference voltage signal S12, "Low" is output as the PWM signal S13, and when the level of the triangular wave signal S11 is lower than the external control reference voltage signal S12. , PWM signal S13
Outputs “Hi”. If the motor M has settled at a constant rotational speed, the external control reference voltage signal S12 is not changed. However, if the rotation of the motor M is to be increased, the level of the external control reference voltage signal S12 is increased. Of the control reference voltage signal S12 of FIG.
As a result, the PWM signal S13 changes, and the “P
The state of “WM on” and the state of “PWM off” can be switched.

Here, the operation in the section A will be described. In the first half of the section A, the switching element 111 and the switching element 116 are "ON", and in the second half of the section A, the switching element 112 and the switching element 116 are "ON". "are doing. Similarly, in the section B, the switching element 112 and the switching element 114 are “ON” in the first half of the section B, and the switching element 113 and the switching element 114 are “ON” in the second half of the section B.
are doing.

However, it can be seen that the PWM signal S13 that is directly involved in the operation control of the motor M has different waveforms in the section A and the section B. That is, the rotation frequency of the motor M can be controlled to be faster or slower by the control reference voltage signal S12. However, since the triangular wave signal S11 is a fixed frequency, the motor M operates at a constant rotation frequency. However, when the section A and the section B are partially observed, the PW
The M control (the degree of generation of the torque of the motor M) is different. This means that there are (1) deviations in the driving time and (2) deviations in the driving period, which are the causes of fluctuations in the rotational speed (jitter). In short, in section A, "P
The number of times "WM off" is four times, while the number of times "PWM off" is three times in section B. The timing of "on" and "off" in each section is also different. The above is the operation of the conventional PWM control circuit device.

[0015]

In the above-described conventional PWM control circuit device, a multi-phase motor of two or three or more phases is driven, and particularly, the motor M is driven at a high speed to drive the motor. In equipment that requires precision rotation speed fluctuation (jitter), the energy (current) given to the motor M because the excitation of each phase is not stable (constant) during each phase and at the time of each commutation Is not constant, and the jitter of the motor M deteriorates. Therefore, in order to keep the energy for each commutation constant by providing high-precision and large-scale hardware, the motor M is controlled using an external clock. The problem has been solved by synchronizing the rotational frequency with the carrier frequency, or detecting the rotational speed of the motor M and applying feedback to the variable carrier frequency to synchronize. However, there have been problems that an external signal input terminal and a multi-stage frequency divider are required, and the scale of the feedback circuit is increased.

The present invention has been made in order to solve such a problem, and does not require an external clock signal, is a small-scale circuit, and uses a simple method to determine the rotational frequency of the motor M and the PWM. Synchronization with the carrier frequency enables high-accuracy and high-stable jitter characteristics to be achieved by maintaining a constant on-time and off-time ratio at any commutation timing and also maintaining a constant control timing. The present invention provides a simple PWM control circuit device.

[0017]

Means for Solving the Problems A PW according to the first invention
The M control circuit device includes a position detection circuit for inputting a position signal indicating a rotation position of the multi-phase motor, a carrier signal reset circuit for inputting a phase signal output from the position detection circuit, and an output from the carrier signal reset circuit. A carrier signal generation circuit that outputs a carrier signal synchronized with a reset signal, a comparator that inputs and compares the carrier signal and an external speed control signal, and outputs a PWM signal; and a phase signal and the PWM signal. And an output element control circuit that outputs a control signal and a switching element that receives the control signal and outputs a motor control signal.

According to a second aspect of the present invention, a PWM control circuit device includes: a position detection circuit for inputting a position signal indicating a rotational position of a polyphase motor; and a phase signal output from the position detection circuit. A carrier signal reset circuit that operates during all commutations, a carrier signal generation circuit that outputs a carrier signal synchronized with the reset signal output by the carrier signal reset circuit, and the carrier signal and an external speed control signal. And a comparator for outputting a PWM signal; and inputting the phase signal and the PWM signal;
An output element control circuit that outputs a control signal, and a switching element that receives the control signal and outputs a motor control signal.

In the PWM control circuit device according to the third invention, the transistors constituting the carrier signal generation circuit, the carrier signal reset circuit, and the comparison circuit use PNP transistors more frequently than NPN transistors.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

Embodiment 1 First, a first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a circuit diagram showing a PWM control circuit device according to the first embodiment of the present invention. The difference from the conventional circuit shown in FIG. 9 is that the reset circuit 121 constituted by an NPN transistor connected in parallel with the capacitor C1.
And a triangular wave reset circuit 103 for outputting a whisker pulse signal S10 for controlling the gate (base) of the NPN transistor 121. The other circuit configuration is the same as the conventional circuit including a replaceable configuration. FIG. 3 is a circuit diagram showing the triangular wave generation circuit 102, the comparator 106, the capacitor C1, and the NPN transistor 121. FIG. 4 is a circuit diagram showing an example of the position detection circuit 104 and the triangular wave reset circuit 103. The position detection circuit 104 includes three comparators 201 to 203, receives position signals S1 to S6, and outputs square waves of phase signals S7 to S9. The triangular wave reset circuit 103 outputs two of the phase signals S7 to S9 output from the position detection circuit 104, respectively.
NAND gates 204 to 206 for inputting two signals;
A NAND gate 207 having the outputs of the NAND gates 204 to 206 as its inputs, and a delay circuit 20 for delaying the output signal S21 of the NAND gate 207 by several hundred ns and inverting the signal.
8 and NOT gate 209, and NOT gate 20
9 and an output signal S21, and a NOT gate 211 for inverting and outputting the output signal of the NAND gate 210, and outputs a mustache pulse signal S10.

The triangular wave generating circuit 102 and the comparator 106
Can be realized by the general constant current circuit and the comparison circuit shown in FIG. 3, and the description of the operation is omitted. Further, the operation of the PWM control circuit according to the first embodiment is roughly the same as the operation of the PWM control circuit of the conventional example, so that the newly added triangular wave reset circuit 103 and N
The operation of the PN transistor 121 will be described. FIG.
FIG. 3 is a signal waveform diagram (timing diagram) according to the first embodiment. The output signal S21 of the NAND gate 207 rises in synchronization with the rise of the phase signals S7 to S9, and the phase signal S21 rises.
It is a signal that falls in synchronization with the fall of 7 to S9, and is a signal having a cycle of one third of the phase signals S7 to S9. In addition, the rising timing of the output signal S21 is the timing at which the operation of the switching elements 114 to 116 on the L side switches, and the falling timing of the output signal S21 is the switching timing of the switching elements 111 to 111 on the H side.
This is the timing at which the operation of 113 is switched. The timing for generating the whisker-like pulse signal S10 is based on the output signal S21.
It is at the time of rising. That is, current path (2), current path
(4) and when switching to the current path (6). The pulse width is the time delayed by the delay circuit 208. The beard pulse signal S10 is input to the base of the NPN transistor 121, and the beard pulse signal S10 is
The transistor 121 is turned “on” for a delay time, and NP
The N-transistor 121 instantaneously discharges (resets) the charge stored in the capacitor C1 while it is "ON". After the discharge is completed, the beard-shaped pulse signal S10 becomes NPN
The transistor 121 is turned off again.

When the NPN transistor 121 is controlled to "on / off" in this manner, the timings T1, T2, T at which the switching elements 114 to 116 on the L side are switched.
3. The capacitor C1 is forcibly discharged (reset) every T4.
Then, the triangular wave signal S11 that repeats the charging can be generated from the triangular wave generation circuit 102. This triangular wave signal S11 is synchronized with an output signal S21 generated based on the phase signals S7 to S9. That is, the triangular wave signal S11
Is synchronized with the rotation frequency of the motor M. As a result, when observing the PWM signals S13 in the sections A and B,
The time of "PWM on" and the time of "PWM off" match, and the timing of "PWM on" can also match the timing of "PWM off". The same applies to other commutation timings other than this section. Therefore, since the on / off time and the on / off timing can be matched at any commutation timing, the rotation speed fluctuation (jitter) of the motor M can be made extremely stable.

As described above, according to the PWM control circuit device of the first embodiment, a simple carrier signal reset circuit can be operated with a small-scale circuit that does not require an external clock signal. Is used as a reference for motor control every time the drive phase of the motor switches.
Since the WM carrier signal is synchronized with the rotation frequency of the motor M, the “PWM on” time is matched with the “PWM off” time, and the “PWM on” timing is also matched with the “PWM off” timing. Accurate and highly stable jitter characteristics can be obtained.

In the first embodiment, the phase signal S7
Although the case where the output signal S21 inside the triangular wave reset circuit 103 is generated using the NAND gates 204 to 207 based on S9 to S9 has been described, the motor M itself can output the FG signal corresponding to the output signal S21. A motor may be used and the number of NAND gates 204 to 207 may be reduced, and the same effect as in the first embodiment can be obtained.

In the first embodiment, the case where the position signals S1 to S6 are generated using the Hall elements H1 to H3 has been described. However, a sensorless drive type motor having a mechanism for reading back electromotive force of the motor is described. FG using
From the signal, the output signal S inside the triangular wave reset circuit 103
21 may be generated, and an effect similar to that of the first embodiment is exerted.

In the first embodiment, the case where a MOS transistor is used as a switching element has been described. However, as shown in FIG.
5 may be replaced with a circuit capable of driving a bipolar transistor, and the switching element may be replaced with a bipolar transistor, which has the same effect as in the first embodiment.

In the first embodiment, the triangular wave reset circuit 103 in the case of a three-phase motor has been described. However, the triangular wave reset circuit 103 is operated at the time of phase switching, and is constituted by a two-phase or more multi-phase motor. Alternatively, the same effect as in the first embodiment may be obtained.

Embodiment 2 FIG. Next, a second embodiment of the present invention will be described with reference to FIGS.

FIG. 6 is a circuit diagram showing a triangular wave reset circuit 103 according to the second embodiment of the present invention. FIG. 4 shown in the first embodiment is different from FIG. 4 in that NOT gate 21 inverts output signal S21 inside triangular wave reset circuit 103.
2, a NAND gate 213 for receiving the output of the NOT gate 212 and the output of the delay circuit 208, and a NAND gate 213 connected between the NAND gate 210 and the NOT gate 211.
Output of D gate 210 and NAND gate 213 is NAN
The difference is that a NAND gate 214 for D is provided. FIG.
FIG. 8 is a diagram showing a signal waveform diagram (timing diagram) in the third embodiment. In the first embodiment, the timings T1, T
2, commutation (2), commutation (4) and commutation (6) indicated by T3
, The whisker-like pulse signal S10 is generated at the time of the commutation (1), the commutation (3) and the commutation (5) indicated by the timings T1 ', T2', and T3 '. The pulse signal S10 may be generated. If the whisker-like pulse signal S10 is generated during all commutations, the accuracy is further improved, which is particularly effective for controlling the motor M that rotates at high speed.

As described above, according to the PWM control circuit device of the second embodiment, the first embodiment
In addition to the effects described above, the following effects can be obtained. That is, since the triangular wave reset circuit 103 generates the whisker-like pulse signal S10 at all commutations, the time and timing of the carrier signal can be synchronized in finer units.

Embodiment 3 Next, a third embodiment of the present invention will be described with reference to FIG.

In FIG. 3, a triangular wave generating circuit 102
The connection between the capacitor C1 and the NPN transistor 121 is reversed so that the capacitor C1 and the transistor 121
Can be connected to the Vcc side. In the case of such connection, the NPN transistor and the PNP transistor forming the triangular wave generation circuit 102, the reset circuit 121, and the comparator 106 of the first embodiment shown in FIG. The configuration is such that the polarity of the whisker-like pulse signal S10 is input in reverse with the transistor. FIG. 8 shows the triangular wave generation circuit 102, the reset circuit 121, and the comparator 106 according to the third embodiment. The operation according to the third embodiment is the same as the operation according to the first embodiment, and a description thereof will not be repeated. Embodiment 3 can also be implemented in Embodiment 2.

As described above, according to the PWM control circuit device of the third embodiment, the first embodiment
Alternatively, in addition to the effects described in the second embodiment, the following effects can be obtained. That is, in the configuration of the triangular wave generation circuit 102, the reset circuit 121, and the comparator 106, PNP transistors are used more than NPN transistors.
The pattern layout area can be further reduced.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a PWM control circuit device according to a first embodiment of the present invention.

FIG. 2 is a timing chart showing an operation of the PWM control circuit device according to the first embodiment of the present invention.

FIG. 3 is a circuit diagram showing a carrier signal generation circuit of the PWM control circuit device according to the first embodiment of the present invention.

FIG. 4 is a circuit diagram showing a reset control circuit of the PWM control circuit device according to the first embodiment of the present invention.

FIG. 5 is a circuit diagram showing a modified example of the PWM control circuit device according to the first embodiment of the present invention.

FIG. 6 is a circuit diagram showing a reset control circuit of a PWM control circuit device according to a second embodiment of the present invention.

FIG. 7 is a timing chart showing an operation of the PWM control circuit device according to the second embodiment of the present invention.

FIG. 8 is a circuit diagram showing a carrier signal generation circuit of a PWM control circuit device according to a third embodiment of the present invention.

FIG. 9 is a circuit diagram showing a PWM control circuit device according to a conventional example of the present invention.

FIG. 10 is a timing chart showing an operation of a PWM control circuit device according to a conventional example of the present invention.

[Explanation of symbols]

100 is a PWM control circuit device, 101 is a speed control circuit,
102 is a triangular wave generation circuit, 103 is a triangular wave reset circuit, 104 is a position detection circuit, 105 is an output element control circuit, 106 is a comparator, 111 to 116 are switching elements, 121 is an NPN transistor, 201 to 203 are comparators, 204 to 207 and 210 are NAND gates,
208 is a delay circuit, 209 and 211 are NOT gates, C1 is a capacitor, G1 to G6 are switching element control signals, H1 to H3 are Hall elements, R1 is a current detection resistor, R2 and R3 are limiting resistors, and S1 to S6 are Position signals, S7 to S9 are phase signals, S11 is a triangular wave signal, S12
Is a control reference voltage signal, S13 is a PWM signal, S10 is a beard pulse signal, and S21 is an output signal.

Claims (3)

[Claims] 1. A position detection circuit for inputting a position signal indicating a rotational position of a multi-phase motor, a carrier signal reset circuit for inputting a phase signal output from the position detection circuit, and a reset output from the carrier signal reset circuit. A carrier signal generation circuit that outputs a carrier signal synchronized with the signal,
A comparator that inputs and compares the carrier signal and an external speed control signal and outputs a PWM signal; an output element control circuit that inputs the phase signal and the PWM signal and outputs a control signal; A PWM control circuit device comprising: a switching element that inputs a control signal and outputs a motor control signal. 2. A position detection circuit for inputting a position signal indicating a rotation position of a multi-phase motor, and a carrier signal reset for inputting a phase signal output from the position detection circuit and operating at all commutations of the multi-phase motor. A circuit, a carrier signal generation circuit that outputs a carrier signal synchronized with a reset signal output from the carrier signal reset circuit, and a comparison that inputs and compares the carrier signal and an external speed control signal and outputs a PWM signal. A PWM control circuit device, comprising: a switch, an output element control circuit that receives the phase signal and the PWM signal, and outputs a control signal, and a switching element that receives the control signal and outputs a motor control signal. 3. The transistor according to claim 1, wherein the carrier signal generation circuit, the carrier signal reset circuit, and the comparison circuit use PNP transistors more than NPN transistors. PWM control circuit device.