JPS63277433A - Voltage regulator of charging generator - Google Patents

Abstract

PURPOSE:To obtain desired duty ratio without trimming resistance by adopting digital system, and to prevent electrolytic corrosion by setting up switching elements on the high potential side of a field winding to permit high-tension drive. CONSTITUTION:The current from an armature winding 1 of an engine-driven generator is rectified with a rectifier 3 to charge a battery 4. A voltage regulating device 6 detects the voltage of the battery 4 and operates the current that flows through a field winding 2 of generator through a power MOSFET 11 so as to keep this value constant. The MOSFET 11 is modulated by the output of an OR gate 20. The basic modulation is performed in synchronization with an oscillation circuit 15. When the generator does not revolve, no voltage is set up to a terminal P of the voltage regulating device 6, so that the output of the OR gate is of a 1/4 duty in stationary state. When the engine is started, this duty is restored as before and the voltage control is performed by the actuation of a boosting circuit 17.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a voltage regulating device for a charging generator, and in particular, to appropriate initial excitation of a generator for charging an on-board battery and a switch element that continues an excitation current. IC that enables high voltage drive
The present invention relates to a voltage regulating device that is advantageous for

[Conventional technology]

Conventionally, in so-called IC regulators that continue the excitation current of the generator using a power transistor, the power transistor is kept in a steady state from the time the key switch is turned on, and the initial excitation current is supplied from the battery to the field winding of the generator. In the case where the battery is allowed to flow, there is a problem in that if the key switch is forgotten to be turned off when the engine is stopped, the battery is discharged through the field winding in a short period of time, resulting in over-discharge.

As a solution to this problem, Japanese Patent Laid-Open Publication No. 140112/1983.

It has been proposed to limit the initial excitation current by continuously controlling the power transistor at an appropriate duty ratio using an oscillation signal from a single oscillation circuit from the time the key switch is turned on until the generator reaches a predetermined power generation state. .

[Problems to be solved by the invention] In the above proposal, the oscillation circuit is a holding circuit that generates a signal with an asymmetric waveform, and in order to obtain a signal with a desired duty ratio (14.3% in the above proposal), It is necessary to adjust the value of the resistor or capacitor in the oscillator circuit. Conventionally, in on-vehicle charging generators, it has been common for the voltage regulator to be constructed from a hybrid thick film integrated circuit and built into one generator. This is usually done by cutting it using a different method.

This increases the manufacturing cost of the IC. Also, a power MO8-FET is used as a switch element.

Cost-effective monolithic IC for the entire voltage regulator
In this case, it is impossible to adjust the resistance value by trimming as described above.

The conventional technology also has the following problems. In other words, in conventional IC regulators, the power transistor, which is a switching element, is generally connected to the low potential side of the field winding, and the battery voltage is always applied to the high potential side of the field winding. Therefore, if salt adheres to the rotor of a generator, even if the power transistor is off,
Leakage current flows from the slip ring that energizes the field winding on the rotor, through the rotor shaft, bearings, and into the generator housing, easily causing electrolytic corrosion.

Such leakage current can be eliminated by connecting the switch element to the high potential side of the field winding, but in order to drive the switch element, a drive power source with a voltage higher than the battery voltage is required, making it difficult to use an IC. It was difficult.

An object of the present invention is to be able to generate an initial excitation signal with a desired duty ratio without adjustment, and to drive the initial excitation signal generation circuit and the booster circuit with one oscillation circuit. It is installed on the high potential side of the line and can be easily driven at high voltage. Especially all the circuits are 1
An object of the present invention is to provide a voltage regulating device for a charging generator that is advantageous when mounted on a monolithic RC chip.

[Means for solving problems]

The above object has an oscillation circuit that generates a signal with an arbitrary duty ratio, and a multi-stage frequency divider that divides the oscillation signal of the oscillation circuit, and a combination of these divided signals generates a signal with a desired duty ratio. an initial excitation signal generation circuit that synthesizes the oscillation signal of the oscillation circuit, a booster circuit that boosts, rectifies, and outputs an AC signal consisting of the oscillation signal of the oscillation circuit and its opposite phase signal, and a booster circuit that boosts, rectifies, and outputs the The oscillation signal of the oscillation circuit is input to the booster circuit in synchronization with the output signal of the excitation signal generation circuit, and the corresponding output signal of the booster circuit connects the battery and the booster winding of the generator. The initial excitation of the generator is performed by intermittent control of the switch element, and when the generator is in a predetermined power generation state, the input of the oscillation signal to the booster circuit is controlled by the output signal of the voltage detection circuit that detects the battery voltage. This is achieved by providing excitation control means for controlling the switching element on and off in accordance with the battery voltage.

[Effect]

The above-mentioned initial excitation signal generation circuit divides an oscillation signal with an arbitrary duty ratio using a multi-stage frequency divider and logically combines these divided signals to synthesize a pulse signal with a desired duty ratio. FIG. 3 shows an example of generating a duty ratio signal of 1/4. Since the duty ratio of this composite signal is constant regardless of the values of the resistance and capacitor of the oscillation circuit, an initial excitation signal with a desired duty ratio can be generated without adjustment.

The booster circuit is a circuit that uses a capacitor and a diode to boost and flow a high-frequency AC signal consisting of an oscillation signal from an oscillation circuit and its opposite phase signal, and is connected to the high potential side of the field winding. A voltage sufficient to drive a switch element such as a power MO5-FET at high voltage is generated. Therefore, when the generator is in a non-generating state, by inputting the oscillation signal of the oscillation circuit to the booster circuit in synchronization with the output signal of the initial excitation signal generation circuit, the switch element is turned on and off at a desired duty ratio. A limited initial excitation current can be passed through the field winding of one generator. Also 1
In a predetermined power generation state of the generator, if the input of the oscillation signal to the booster circuit is controlled by the output signal of the voltage detection circuit that detects the battery voltage, the switching element is controlled intermittently according to the battery voltage, Normal voltage adjustment operation will occur. This makes it possible to use one oscillation circuit as a drive power source for both the initial excitation signal generation circuit and the booster circuit, thereby realizing high-voltage drive of the switch element that intermittents the excitation current.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall circuit diagram of an embodiment of a charging generator voltage regulator according to the present invention. In FIG. 1, 1 is an armature winding of a generator driven by an engine (not shown); They are connected in a star pattern. 2 is a field winding that generates field magnetic flux;
3 is a three-phase full-wave rectifier that converts the three-phase AC output of the armature winding 1 into DC, and 4 is a battery, which is charged by the DC output rectified by the three-phase full-wave rectifier 3, or is connected to an external load (
(not shown). Reference numeral 5 denotes a key switch, which is turned on when the engine is running to energize an ignition device (not shown) and the like. 6 is a voltage regulator which is the main part of the present invention, and includes an N-channel power MO8-FET 11 as a main switch element, a flywheel diode 12. A constant voltage circuit consisting of a resistor 13 and a Zener diode 14, NOT gates 151, 152. Oscillation circuit 152 consisting of resistor 153° and capacitor 154 Voltage dividing resistor 16
1,162. Capacitor 163. Voltage detection circuit 16 consisting of NOT gate 164. NOT gate 171, 172
, 173. Capacitor 174°177, diode 17
A booster circuit 17 consisting of 5,176,178. Initial excitation signal generation circuit 18゜Power generation detection circuit 1 as excitation control means
9. OR gate 20. AND gates 21, 22. NOT
N-channel M as OR gate 20 auxiliary switching element
It is composed of O8-FET24.

Among these, power MO8-FETI 1 is connected between the S terminal on the generator output side and the S terminal on the high potential side of the field winding 2, and its conduction supplies an exciting current to the field winding 2. The flyhole diode 12 is connected to the S terminal and the S terminal (
(earth) and conducts the flywheel current of the field winding 2. MOS-FET24 is
It is connected between the gate of MO-8-FET11 and the S terminal, and its conduction causes the power MO8-FET II to
discharges the charge accumulated in the gate of the One end of the resistor 13 of the constant voltage circuit is connected to the key switch 5 through the power terminal, and the voltage dividing resistor 161.16 of the voltage detection circuit 16
2 is connected between the S terminal and the S terminal, and divides the battery voltage input through the S terminal. In addition, the terminal of the power generation detection circuit 19 is connected to the armature winding 1 through the S terminal.
The generated voltage is inputted.

FIG. 2 is a detailed circuit diagram of the initial excitation signal generation circuit 18 and the power generation detection circuit 19 shown in FIG. The initial excitation signal generation circuit 18 includes a frequency divider 181 configured by connecting N stages of T-type flip-flops in series, a T-type flip-flop 182 that constitutes the N+1 stage frequency divider, and an AND gate 183. , the power generation detection circuit 19 has a resistor 191 . It consists of a capacitor 192° and NOT gates 193 and 194.

The output of the AND gate 183 of the initial excitation signal generation circuit 18 and the output of the NOT gate 194 of the power generation detection circuit 19 are O.
It is connected to the input of R gate 20.

The operation of the circuit configured as described above will be explained below in order. First, when the car engine is stopped, turn on the key switch 5.

Zener power is supplied from battery 4 through resistor 13.
A constant voltage Voo is generated in the diode 14, and supplies a power supply voltage to each logic gate. Then, the oscillation circuit 15
53. The duty ratio of the six oscillation signals that start oscillating at a period determined by the capacitor 154 is arbitrary, and is set to 1/2, for example.

The oscillation signal of the oscillation circuit 15 is input to the terminal a of the initial excitation signal generation circuit 18. In FIG. 2, the frequency of the oscillation signal input to terminal a is changed to 1/2N by frequency divider 181.
The frequency is divided by a factor of two. FIG. 3(a) shows the frequency-divided signal waveform. After this, further T-type flip-flop 182
The frequency is divided by 172 to obtain the signal waveform shown in FIG. 3(b). An AND gate 183 performs a logical product of (a) and (b).

A signal having the waveform shown in FIG. 3(C) is output. Figure 3 (
The pulse off time t2 in the waveform C) is three times the pulse on time 11, and the duty ratio is.

D=t5/(tz+t2)=1/
It becomes 4. This value is the resistor 153 of the oscillation circuit 15. It is constant regardless of the value of the capacitor 154.

At this point, the generator is not generating power, and no voltage is generated in the armature winding 1. Therefore, the P terminal of the voltage regulator 6 has no voltage, and the input to the B terminal of the 1 power generation detection circuit 19 in FIG.
The output of OT gate 193 is #1 level, NOT gate 1
The output of #94 is 20 lbel, and this #O lbel signal is input to the OR gate 20, so from the C terminal, that is, the output terminal of the OR gate 20, the signal with the waveform shown in FIG. Output.

On the other hand, since the battery 4 is not charged, its terminal voltage, that is, the voltage at the S terminal, does not reach the specified value (usually about 14.5 V), and the resistors 161 and 162 of the voltage detection circuit 16
Since the divided voltage does not reach the threshold of the NOT gate 164, the output of the NOT gate 164 becomes #1 level, and this 11 level signal is input to the AND gate 22. At this point, the other input of the AND gate 22 is connected to the C terminal.

An output waveform of the C terminal, that is, a signal having the waveform shown in FIG. 3 (Q) is output from the output terminal of the AND gate 22,
The signal output from this AND gate 22 is input to the AND gate 21 together with the oscillation signal of the oscillation circuit 15.

Here, when the output of the AND gate 22 is 81' and O'
Explain the operation in the case (assuming Voo=10V)
.

(i) When the output of the AND gate 22 is #1'', the oscillation signal of the 1 oscillation circuit 15 is output as is to the output of the AND gate 21, and is transmitted to the boost circuit 17. Booster circuit 1
7, the outputs of the NOT gate 171 and the NOT gate 173 are in opposite phase to each other, and the voltage is boosted by the operation described below.

Now, let the output of NOT gate 171 be #1 level, and NO
When the output of the T-gate 173 is ``θ level, the capacitor 174 is charged through the diode 175, and after a predetermined time, the voltage between the terminals of the capacitor 174 becomes IOV, which is 0.
Next, the phase is reversed and the output of NOT gate 173 becomes a
1 level, and the output of NOT gate 171 becomes O# level.

The voltage at the anode of diode 176 is IOV+10V=
The voltage becomes 20V, and the charge passes through the diode 176 and moves from the capacitor 174 to the capacitor 177. The voltage appearing on the capacitor 177 due to this charge movement varies depending on the capacitance ratio of the capacitors 174 and 177, but the capacitor 177 is charged to a voltage at least higher than IOV. Furthermore, when the phase is reversed and the output of the NOT gate 171 becomes 11 levels, the voltage at the anode of the diode 178 becomes 20 V or more, and the charge passes through the diode 178 and moves to the gate of the P'7-M08-FET11. do.

As a result, a voltage exceeding the threshold value is applied between the gate and source of the power MO8-FET II, and the power MO8-FET II becomes conductive.

(n) If the output of AND gate 22 is 'O' (7), then AN
The output of D gate 21 becomes 10g level, and oscillation circuit 1
Since the output of No. 5 is not transmitted to the booster circuit 17, no boosting is performed. On the other hand, since the NOTOR gate 20 force is 91 lvl, this signal causes the MOS-FET24
becomes conductive and discharges the charge stored in the gate of power MO5-FETII.

Power MO8-FETII is in a cutoff state.

With the above operation, the power MO8-FETI 1 is
Conduction and disconnection are repeated in synchronization with the waveform shown in FIG. 3(c), and in this state, a current limited to 1/4 of the maximum current continues to flow through the field winding 2.

Next, when the engine starts and starts rotating, armature winding 1
A voltage is generated at b of the power generation detection circuit 19 via the P terminal.
input to the terminal. When the average value of this voltage exceeds a predetermined value, the output of NOT gate 193 becomes 40g level, NOT
Since the output of gate 194 becomes #1 level, the output of OR gate 20 remains at level 1, and the duty ratio signal 174 from initial excitation signal generation circuit 18 is no longer transmitted. Therefore, the output state of AND gate 22 is determined by the output of NOT gate 164.

When the voltage of the battery 4 is low, the output of the NOT gate 164 is 11 lvl, and is transmitted as it is to the AND gate 21 through the AND gate 22, so that the oscillation circuit 1
The oscillation signal No. 5 is input to the boost circuit 17, and the boost circuit 17
Due to this operation, the power MO8-FETI 1 maintains the conductive state.

Then, the current flowing through the field winding 2 increases and the voltage generated in the armature winding 1 increases, so that the voltage of the battery 4 also increases. When the voltage of battery 4 exceeds the specified value, N
The output of OT gate 164 is inverted to 10 Lebel. Then, the output of the AND gate 22 becomes 40 g level, and the output of the AND gate 21 becomes #0 level, so the oscillation signal of the 1st oscillation circuit 15 is no longer transmitted to the booster circuit 17, so no boosting is performed and the power MO8-FET 11 is in a cut-off state. The current flowing in the field winding is attenuated through the flywheel diode 12. Therefore, the voltage of the battery 4 is adjusted by repeating the operation of 0 or more in which the generated voltage decreases and the voltage of the battery 4 also decreases.

According to this embodiment, a duty ratio signal of 1/4 required for initial excitation can be generated without adjustment, and trimming of resistors, capacitors, etc. of the 1 oscillation circuit is not required. By incorporating the circuit, it becomes possible to realize a one-chip voltage regulator. Furthermore, since one oscillation circuit can drive both the initial excitation signal generation circuit and the booster circuit, manufacturing costs can be kept to a minimum.

In the above embodiment, a method of generating a duty ratio signal of 1/4 was described, but it is also possible to synthesize any desired duty ratio signal by increasing the frequency division ratio of a single oscillation signal and using combinatorial logic. is possible.

〔Effect of the invention〕

According to the present invention, when the generator is in a non-generating state, the initial excitation current flowing through the field winding is limited to prevent over-discharging of the battery due to forgetting to turn off the key switch, etc.
A switch element that cuts off the excitation current is installed on the high potential side of the field winding, making it possible to drive at high voltage.1 Suppressing leakage current caused by salt buildup on the generator rotor.
Electrolytic corrosion can be prevented.

Moreover, since initial excitation can be performed by intermittent control of the switching element at a desired duty ratio using a digital circuit, there is no need for adjustments such as ill wait trimming, and one oscillation circuit can be used as an initial excitation signal generation circuit. Manufacturing costs can be reduced by sharing the drive power supply for the booster circuit and the booster circuit.

Further, since no adjustment is required, it becomes possible to mount the voltage regulator on a single-chip monolithic IC, which has the effect of reducing the size of the device.

[Brief explanation of the drawing]

Fig. 1 is an overall circuit diagram of an embodiment of the charging generator voltage regulator according to the present invention, Fig. 2 is a detailed circuit diagram of the initial excitation signal generation circuit and power generation detection circuit in Fig. 1, and Fig. 3 is an initial FIG. 3 is a signal waveform diagram for explaining the operation of the excitation signal generation circuit. 2... Field winding, 4... Battery, 6... Voltage regulator, 11... Power MO8-FET, 15...
Oscillation circuit, 16... Voltage detection circuit, 17... Boost circuit, 18... Initial excitation signal generation circuit, 19... Power generation detection circuit, 20-23... Logic gate for excitation control, 1
81,182... Branch unit.

Claims (1)

[Claims] 1. A switch element connected between a battery and a field winding of a generator that charges the battery, and for intermittent excitation current of the field winding, and operation of the switch element according to the voltage of the battery. A voltage regulating device for a charging generator having a voltage detection circuit for controlling an oscillation circuit that generates a signal with an arbitrary duty ratio, and a multi-stage frequency divider that divides the frequency of the oscillation signal of the oscillation circuit, an initial excitation signal generation circuit that synthesizes a signal with a desired duty ratio by combining the frequency-divided signals, and a booster circuit that boosts and rectifies an alternating current signal consisting of the oscillation signal of the oscillation circuit and its opposite phase signal, and outputs the resultant signal. When the generator is in a non-generating state, the oscillation signal of the oscillation circuit is input to the booster circuit in synchronization with the output signal of the initial excitation signal generation circuit, and the corresponding output signal of the booster circuit causes the switch to be activated. The element is continuously controlled to perform initial excitation of the generator, and when the generator is in a predetermined power generation state,
Charging characterized by comprising excitation control means for controlling the input of an oscillation signal to the booster circuit based on the output signal of the voltage detection circuit to continuously control the switch element according to the battery voltage. Generator voltage regulator.