JPH07213059A - Switching regulator - Google Patents

Abstract

PURPOSE:To make a switching regulator exhibit the power supply capacity to the utmost by equalizing the supply balance between the master and slaves. CONSTITUTION:This switching regulator is equipped with a pulse generator PG which generates pulse signals P0-P2 being shifted by T/n time at a time, and in the master A and slaves B1 and B2, the primary windings of transformers T0-T2, switching elements Q0-Q2, and load resistors RS0-RS2 are connected in series, and DC voltage is applied to its both ends, and the switching elements Q0-Q2 are turned on, according to the pulse signals P0-P2 by logic circuits LOG1-LOG2. And, comparators COM0-COM2 detect that the load voltages generated in load resistors RS0-RS2 have reached error voltage of the DC output voltage, and this regulator stops the ON operation with this detected output, and by this control, it coverts the AC voltage generated in secondary winding into DC voltage, by rectifying and smoothing it, and adds output of each unit in parallel and outputs the sum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching regulator used as a power source for a large power amplifier of a broadcasting machine, for example.

[0002]

2. Description of the Related Art Conventionally, a master-slave type switching regulator is often used in a power supply for a large power amplifier of a broadcasting machine. FIG. 3 shows its general configuration. In FIG. 3, A is a master unit in which a primary winding of a converter transformer T0, a switch element Q0, and a load resistor RS0 are connected in series, and both ends thereof are connected to a DC power input terminal TIN and a return terminal TRTN.
The switch element Q0 is switching-controlled by the output of the comparator COM0, and the on / off state of the switch element Q0 disconnects the DC power supply applied to the primary winding of the converter transformer T0. As a result, the AC voltage generated in the secondary winding is rectified and smoothed by the rectifying / smoothing circuit RF0, converted into a DC voltage, and guided to the output terminals TOUT1 and TOUT2.

Further, the DC voltage appearing at the output TOUT1 is multiplied by, for example, 1 / N by the feedback circuit FB, and then input to the error amplifier OP together with the reference voltage VREF generated by the reference voltage source E. The error amplifier OP detects and outputs an error voltage of the feedback voltage with respect to the reference voltage VREF. The error voltage obtained here is sent to the comparator COM0 and compared with the triangular wave voltage signal generated by the triangular wave generator TG. . Comparator COM
The comparison result of 0 is supplied to the control input terminal of the switch element Q0 as a switching control signal.

On the other hand, B is a slave unit in which a primary winding of a converter transformer T1, a switching element Q1 and a load resistor RS1 are connected in series, and both ends thereof are connected to the DC power input terminal TIN and the return terminal TRTN. There is. The switching element Q1 is switching-controlled by the output of the comparator COM0 of the master unit A, and the on / off switching of the switching element Q1 interrupts the DC power supply applied to the primary winding of the converter transformer T1. As a result, the AC voltage generated in the secondary winding is rectified and smoothed by the rectifying / smoothing circuit RF1 and converted into a DC voltage, which is introduced in parallel to the master unit A to the output terminals TOUT1 and TOUT2.

Although FIG. 3 shows the case where there is one slave unit, it is generally constructed by adding slave units in parallel. That is, in the master-slave system, a stable DC voltage is supplied by applying a switching control signal of the master unit to the switch elements of the slave unit and simultaneously performing switching drive.

However, in the conventional master-slave type switching regulator as described above,
If there are variations in the characteristics (rise time, fall time, etc.) of the switch elements of each unit, and the resistance value when turned on,
A difference in the supply current between the master and slave causes a stable supply.

Although it is conceivable that the variation is preliminarily estimated in each unit to increase the power supply capacity, the size of the apparatus will be increased.
In addition, since the heat generation amount differs between the units, the reliability also varies, and the reliability of the entire device decreases.

[0008]

As described above, in the conventional master-slave type switching regulator, if there are variations in the characteristics of the switch element of each unit, the resistance value when turned on, etc. There is a difference in the current, and stable supply cannot be achieved.

A method may be considered in which this variation is estimated in advance in each unit to increase the power supply capacity, but there is a problem in that the size of the device is increased.
In addition, since the heat generation amount differs between the units, the reliability also varies, and the reliability of the entire device decreases.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a switching regulator capable of equalizing the supply balance between the master and slave and maximizing the power supply capability.

[0011]

In order to achieve the above object, the present invention is to connect a primary winding of a converter transformer, a switch element and a load resistor in series, and connect both ends thereof to a DC voltage input terminal and a return terminal. Then, the error voltage of the DC output voltage with respect to the reference voltage is detected, and the switching element is ON / OFF controlled according to the error voltage level, and by this control, the AC voltage generated in the secondary winding of the converter transformer is rectified and smoothed. Error in the master unit, in which the master unit for converting into a DC voltage with the converter, the primary winding of the converter transformer, the switch element, and the load resistor are connected in series, and both ends thereof are connected to the DC voltage input terminal and the return terminal. ON / OFF control of the switch element is performed according to the voltage level, and by this control, the secondary of the converter transformer is A master-slave system including one or more slave units for rectifying and smoothing an AC voltage generated in a line and converting the AC voltage into a DC voltage, and obtaining a DC output voltage by adding output voltages of the master unit and the slave units in parallel. In the switching regulator,
When a pulse signal having a predetermined period T is generated and the number of master units and slave units is n, the pulse signal is shifted by T / n time and supplied to each unit. A comparator for detecting that the load voltage has reached the error voltage by comparing the error voltage with the load voltage generated in the load resistance in the unit; and the detection of the comparator from the pulse signal input from the pulse generator. A control circuit for turning on the switch element until an input is provided, the slave unit compares the error voltage with a load voltage generated in a load resistor in the unit, and detects that the load voltage reaches the error voltage. The comparator that detects the pulse signal from the pulse signal input from the pulse generator to the detection input of the comparator. Characterized in that the pitch element and to a control circuit for ON control.

Each control circuit of the master unit and the slave unit is an SR flip-flop, which is set by the pulse signal and reset by the detection signal of the comparator, and is turned on by the switch element during a period from set to reset. It is characterized in that a signal is supplied.

[0013]

In the switching regulator having the above structure, the pulse signals generated by the pulse generator are shifted by T / n time and supplied to the control circuits of the master unit and the slave unit, respectively, and the switching elements of the units are turned on in order. To generate a DC voltage. At this time, by utilizing the fact that the load voltage generated in the load resistance increases due to the excitation current generated in the primary winding of the converter transformer, the ON control of the control circuit is stopped when the load voltage reaches the error voltage. ing.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described in detail below with reference to FIGS. In FIG. 1, the same parts as those in FIG. 3 are designated by the same reference numerals, and different parts will be mainly described here.

FIG. 1 shows the configuration of a master-slave type switching regulator according to the present invention. Here, in order to simplify the description, a case where two slave units are connected in parallel will be described.

In FIG. 1, the voltage (hereinafter referred to as an error voltage) output from the error amplifier OP is supplied to one input terminal of the comparator COM0 of the master unit A, and the load resistance is supplied to the other input terminal. The voltage generated at RS0 (hereinafter referred to as load voltage) is supplied.
The comparator COM0 compares the voltage levels of both inputs and outputs a determination signal of H (high) level when the load voltage reaches the error voltage and L (low) level when the load voltage does not reach the error voltage. The determination signal is the logic circuit LOG0.
Is supplied to.

The logic circuit LOG0 is, for example, S-.
Synchronous pulse generator SY composed of R flip-flops
It is set by the fall of the pulse signal generated for the master unit A at G, and the comparator COM0
It is reset by the rise of the determination signal from, and outputs a switching control signal for turning on the switch element Q0 during the period from set to reset.

On the other hand, the slave unit Bi (i is 1,
2) both have the same configuration, and the primary winding of the converter transformer Ti, the switch element Qi, and the load resistance RSi are connected in series, and both ends thereof are connected to the DC power supply input terminal TIN and the return terminal TTRN.

Further, a comparator COMi and a logic circuit LOGi are further provided. Each comparator COMi
The error amplifier O of the master unit A is connected to one input terminal of
The output of P is supplied, and the load resistance RSi is applied to the other input end.
The voltage generated at is supplied.

The respective comparators COMi compare the voltage levels of the two and operate in the same manner as COM0. The determination signal output from each comparator COMi is supplied to the logic circuit LOGi. The logic circuit LOGi receives the pulse signals individually generated by the pulse generator SYG and operates in the same manner as LOG0.

The switch element Qi is a comparator COMi.
Switching is controlled by the output of the DC power supply and the DC power supply applied to the primary winding of the converter transformer Ti is turned on and off. As a result, the AC voltage generated in the secondary winding is rectified and smoothed by the rectifying / smoothing circuit RFi and converted into a DC voltage, which is parallel to the master unit A and output terminal T.
Guided to OUT1 and TOUT2.

The sync pulse generator SYG has a constant period T.
Generates the master pulse signal P0, and the master unit A
To the logic circuit LOG0 of the slave unit B1,
The pulse signals P1 and P2 for B2 are generated.

The operation of the above configuration will be described below with reference to FIG. First, in the synchronous pulse generator SYG, as shown in FIGS. 2 (a), (b), and (c), T / 3
The pulse signals P0, P1, P2 shifted by the period are generated and supplied to the logic circuits LOG0, LOG1, LOG2 of the units A, B1, B2, respectively. Each of the logic circuits LOG0, LOG1, and LOG2 becomes a set state by the fall of the input pulse signals P0, P1, and P2, as shown in FIGS. 2 (h), (i), and (j), and the on signal (H level). ) Is output. Therefore, the switch elements Q0, Q1, Q of each unit A, B1, B2 are
2 is turned on with a delay of T / 3 each.

In the master unit A, when the switch element Q0 is turned on, a current flowing through the primary winding of the converter transformer T0 flows through the load resistor RS0, which generates a load voltage. Here, the exciting current generated in the primary winding of the transformer T0 is added to the current flowing through the load resistor RS0, and gradually increases. Therefore, the load voltage also gradually increases and reaches the output level of the error amplifier OP.

Then, the output of the comparator COM0 goes high.
The logic circuit LO becomes
Since G0 is reset and its output becomes L level,
The switch element Q0 is turned off. When the switch Q0 is turned off, the load voltage becomes 0V and the output of the comparator COM0 is also inverted to L level.

This operation is performed by the slave unit B
The same applies to 1 and B2. When the switching elements Q1 and Q2 are turned on, the current flowing through the primary windings of the converter transformers T1 and T2 flows through the load resistors RS1 and RS2, thereby generating the load voltage. Then, the load voltage gradually increases due to the exciting current, and reaches the output level of the error amplifier OP.

Then, the comparators COM1 and COM2
Output goes high and the logic circuits LOG1 and LPG2 are reset by the rise, and the output goes low and the switch elements Q1 and Q2 are turned off. When the switches Q1 and Q2 are turned off, each load voltage becomes 0 V, and the outputs of the comparators COM1 and COM2 are also inverted to L level.

That is, as shown in FIG. 2D, for example, even if the error voltage changes due to some factor, each unit adjusts the ON period based on the error voltage, so that each unit supplies power in a well-balanced manner. can do.

Therefore, according to the switching regulator having the above-mentioned configuration, the supply balance between the master and slave can be made uniform, so that the power supply capability can be maximized. In this case, since the electrode supply capacity assigned to each unit is minimized, the device does not need to be too large.

In the above embodiment, the number of slave units is two.
Although the case has been described above, the present invention is not limited to this, and a larger number of slave units may be connected in parallel. Needless to say, the present invention can be implemented in the same manner even if various modifications are made without departing from the scope of the invention.

[0031]

As described above, according to the present invention, it is possible to provide a switching regulator capable of equalizing the supply balance between the master and slave and maximizing the power supply capability.

[Brief description of drawings]

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

FIG. 2 is a timing chart for explaining the operation of the above embodiment.

FIG. 3 is a block circuit diagram showing a configuration of a conventional switching regulator.

[Explanation of symbols]

A ... Master unit, B1, B2 ... Slave unit,
T0, T1, T2 ... Converter transformer, Q0, Q1,
Q2 ... switch element, RS0, RS1, RS2 ... load resistance, OP ... error amplifier, COM0, COM1, COM
2 ... Comparator, LOG0, LOG1, LOG2 ... Logic circuit, SYG ... Sync pulse generator, RF0, RF
1, RF2 ... Rectifying / smoothing circuit, P0, P1, P2 ... Pulse signals.

Claims (2)

[Claims] 1. A primary winding of a converter transformer, a switch element and a load resistor are connected in series, both ends of which are connected to a DC voltage input terminal and a return terminal, and an error voltage of a DC output voltage with respect to a reference voltage is detected, A master unit that controls ON / OFF of the switch element according to the error voltage level, and rectifies and smoothes the AC voltage generated in the secondary winding of the converter transformer by this control to convert the AC voltage into a DC voltage. A line, a switch element and a load resistor are connected in series, both ends of which are connected to a DC voltage input terminal and a return terminal, and the switch element is ON / OFF controlled according to the error voltage level obtained by the master unit. Rectifies and smoothes the AC voltage generated in the secondary winding of the converter transformer to convert it to DC voltage. A master-slave switching regulator that includes one or more slave units, and that outputs a DC output voltage by adding the output voltages of the master unit and the slave units in parallel. , A pulse generator that shifts the pulse signal by T / n time and supplies it to each unit, where n is the number of master units and slave units, and the master unit includes the error voltage and A comparator that compares the load voltage generated in the load resistance to detect that the load voltage has reached the error voltage,
And a control circuit for ON-controlling the switch element from the pulse signal input from the pulse generator to the detection input of the comparator, the slave unit, the error voltage and the load voltage generated in the load resistance in the unit, And a comparator for detecting that the load voltage has reached an error voltage, and a control circuit for ON-controlling the switch element from the pulse signal input from the pulse generator to the detection input of the comparator. A switching regulator characterized in that 2. The control circuit of each of the master unit and the slave unit is an SR flip-flop, which is set by the pulse signal and reset by the detection signal of the comparator, and the switch element is set for a period from set to reset. The switching regulator according to claim 1, wherein an ON signal is supplied to the switching regulator.