JPH0811058Y2 - Control circuit - Google Patents

Description

[Detailed Description of the Invention] <Industrial field of application> The present invention relates to a control circuit for a DC stabilized power supply device using a switching regulator. More specifically, the circuit element in the control circuit is formed into an IC and a thin film. By reducing the size and weight, the function and space of the entire device are reduced.

<Prior Art> FIG. 6 is a configuration block diagram showing an example of a conventional DC stabilized power supply device. Reference numeral 10 is a DC / DC converter, and the input DC voltage Vi is applied to the primary winding n1 of the transformer T1 by turning on / off a switching element Q such as a transistor. The alternating output induced in the secondary winding n2 is rectified by the diodes D1 and D2 and further smoothed by the choke coil L and the capacitor C to obtain the output DC voltage V ₀ supplied to the load.

40 receives the output DC voltage V ₀ which DC / DC converter 10, DC / DC converter 10 so that the output DC voltage V ₀ is maintained constant
In the control circuit for controlling the on / off of the switching element Q, the error amplifier 41 that amplifies the error between the output DC voltage V ₀ and the reference voltage Vref, and the pulse width signal of the duty ratio according to the output of the error amplifier 41 are output. The PWM circuit 42 that outputs is
It is configured to be connected to a control circuit 43 for on / off controlling the switch element Q via a transmission transformer T2.

<Problems to be Solved by the Invention> However, in the conventional device having such a configuration, the transmission transformer is large, so that the control circuit is not provided.
It was difficult to make it into an IC, and the entire device became large, and it was not possible to make it smaller and functional.

The present invention has been made in view of such a point, and the transmission transformer is configured with a thin film circuit to be miniaturized. Further, the integrated error amplifier and switch drive circuit are connected on a common substrate, and the number of components is increased. Less mounting workability,
The purpose is to provide a small control circuit.

<Means for Solving the Problems> In order to achieve such an object, the present invention provides an input DC voltage to a primary winding of a transformer which is turned on / off by a switching element and induces it in a secondary winding. In a control circuit for controlling on / off of the switch element so as to maintain a constant output DC voltage of a DC / DC converter that rectifies and smoothes an alternating signal and supplies the load, the output voltage is compared with a reference voltage. An error amplification IC that extracts the error amplified signal obtained as a pulse signal, and a transformer in which the pulse signal is supplied to the primary side coil and an output signal is induced in the secondary side coil is a thin film formed on a ceramic thin film. A transmission transformer; a switch driving IC that receives a pulsed signal obtained from the secondary side of the thin film transmission transformer and controls ON / OFF of the switch; First coil and the circuit of the error amplifier IC as well as connected via the thin-film circuit, said switch driver IC and the second coil of the thin film transmission transformer
And a package for connecting the circuit of (1) through a thin film circuit.

In addition, the input DC voltage is turned on / off by the switch element and applied to the primary winding of the transformer, and the output DC voltage of the DC / DC converter that supplies the load by rectifying and smoothing the alternating signal induced in the secondary winding. In a control circuit for controlling ON / OFF of the switch element so as to keep constant, on one surface, an error amplification IC for extracting an error amplification signal obtained by comparing the output voltage with a reference voltage as a pulse signal
And a thin film transmission transformer in which the pulse signal is supplied to the primary coil, and the other side receives a secondary coil of the thin film transmission transformer and a pulsed signal obtained from the secondary coil. A ceramic substrate having a switch driving IC for controlling ON / OFF of the switch, a circuit of the error amplification IC is connected to an external circuit via a thin film circuit, and a circuit of the switch driving IC is connected to the thin film circuit. And a package that is connected to an external circuit via the.

<Operation> The primary coil of the thin film transmission transformer receives the excitation energy from the error amplification IC, magnetic flux is generated in the magnetic film, and the output voltage corresponding to the input voltage is obtained in the secondary coil. The signal output from the thin film transmission transformer is an IC for driving the switch.
And is controlled to turn on / off the switch element of the DC / DC converter.

<Embodiment> An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an overall structural conceptual diagram of the DC stabilized power supply device of the present invention, which is characterized in that the transmission transformer is formed of a thin film. Incidentally, in FIG. 1, components having the same functions as those in FIG. In the figure, 11 is a control circuit composed of a thin film, which receives the output DC voltage V ₀ of the DC / DC converter 10, and the output DC signal V ₀ of the DC / DC converter 10 is kept constant. ON / OFF of the switch element Q is controlled.

12 is a thin film transmission transformer in which an error amplification signal obtained by comparing the output DC voltage V ₀ and the reference voltage Vref is used as a pulse signal.
An integrated error amplification circuit provided to the primary side of 20, which is composed of an error amplifier 13, a modulator 14, and an oscillator 15. The error amplifier 13 compares the output DC voltage V ₀ of the DC / DC converter 10 with the reference voltage Vref, and transmits a signal obtained by amplifying the error to the modulator 14. The modulator 14 uses the frequency fo from the oscillator 15.
The error amplification signal is amplitude-modulated by the alternating signal of sc, and the high-frequency error signal is converted into a high-frequency error signal.
Supply to.

Reference numeral 16 denotes an integrated switch drive circuit that receives a pulse-shaped signal obtained from the secondary coil 21 'of the thin film transmission transformer 20 and controls ON / OFF of the switch element Q.
It is composed of a PWM circuit 18. The output induced in the secondary coil 21 'is converted from a high frequency signal into an original error signal by a demodulator 17 including a rectifier and a low pass filter (both of which are not shown), and is transmitted to a PWM circuit 18. . PWM circuit 18
Applies a pulse signal with a duty ratio corresponding to this error amplification signal to the switch element Q to turn it on / off, and
The output DC voltage V ₀ of the converter 10 is controlled.

FIG. 2 is a configuration diagram of the thin film transmission transformer 20 used in the control circuit. (A) is a plan view and (B) is A-.
It is an A'cross section figure. In the figure, 20 is a thin film transmission transformer formed of a thin film in order to make the control circuit into a hybrid IC. The control circuit is connected to the integrated error amplification circuit and switch drive circuit on a common substrate (not shown). To form. 22 is a highly insulating ceramic substrate such as sapphire or AIN, which has a surface smoothness equivalent to that of a silicon wafer, and has a substantially square shape with a thickness g and a length L of a piece. 21 and 21 'are ceramic substrates 22
Is a thin film coil formed in a spiral shape on each surface, and is formed of a metal having good electric conductivity such as aluminum or copper. Since the thin film coils 21 and 21 'are formed by patterning a metal such as aluminum coated on both surfaces of the ceramic substrate 22 in a vacuum by double-sided exposure, a coil having an arbitrary number of turns n can be formed in a fine pattern. Further, the coil patterns can be accurately overlapped on both surfaces. In the drawings below, ceramic substrate 22
The structure of the back surface of the above is indicated by adding a ′ to the reference numeral, and the same operation as that of the reference numeral provided on the front surface of the substrate is assumed.

21a and 21a 'are thin film coils for connecting to an external circuit.
Electrodes provided at both ends of 21, 21 ', one of which is a pad connected by wire bonding made of aluminum, and the other of which is a face-down connected bump formed of solder. ing. Reference numeral 23 is an insulating layer formed on the thin film coil and made of SiO ₂ , Al ₂ O ₃ or the like, and is patterned along the pattern of the thin film coil in a photolithography process after film formation. Reference numeral 24 is a magnetic thin film of a ferromagnetic material further laminated on the insulating layer 23, and a metal such as permalloy or ferrite is formed by vacuum coating or electroless plating.

The thin-film transmission transformer 20 configured in this way has the thin-film coil 21 (referred to as the primary coil 21) starting from the one electrode portion 21a.
When a pulsed signal of voltage v1 is applied to the thin film coil
A voltage v2 corresponding to the pulsed voltage v1 applied to the primary coil 21 is induced in 21 '(referred to as a secondary coil 21').

FIG. 3 is a cross-sectional view of the thin film transmission transformer shown in FIG. 1 and illustrates a structure for causing the magnetic flux generated in the primary coil 21 to intersect the secondary coil 21 'without loss.
In the figure, components having the same functions as those in FIG. When a pulsed voltage v1 is applied to the primary coil 21 and a current flows through the primary coil 21, a magnetic flux Φ is generated in the magnetic thin film 24. Part of the magnetic flux Φ is the ceramic substrate
The magnetic flux Φ1 passing through 22 and the magnetic flux Φ2 in the magnetic thin film 24 are spread in the X range. That is, for magnetic flux Φ, Φ = Φ1 +
The relationship of Φ2 is established.

Further, the magnetic flux Φ2 has a relationship shown in the following equation, and (d ² Φ2 / dx ² ) − (2 / μs · g · t) · Φ2 = 0.

Here, x is the distance from the coil end of the outermost shell of the primary coil 21, μs is the relative permeability of the magnetic thin film 24, and g is the ceramic substrate.
The thickness of 22 and the thickness t of the magnetic thin film 24 are shown (λ is a thin film material and a ceramic substrate constituting the thin film and can be considered to be a constant value for the thin film transmission transformer 20).

From this, for example, the magnetic flux Φ obtained by the primary coil 21
In order to supply 99% or more of the above to the secondary coil 21 ', it is understood that the distance of x should be set to x ≧ 5λ. That is, by increasing the distance x at which the magnetic thin film is provided, the magnetic flux Φ generated in the primary coil 21 can be transmitted to the secondary coil 21 ′ without loss.

FIG. 4 is an exploded perspective view of the control circuit of the DC stabilized power supply of the present invention. Reference numeral 20 is a thin film transmission transformer, 12 is an error amplification IC including an error amplifier and a modulator, and 16 is a switch driving IC including a demodulator and a PWM circuit. IC12 for error amplification and IC16 for driving switches are packaged
The bumps 21'a of the thin film transmission transformer 20 are connected to the pads 30a of the conductor pattern by the solder bump technique by face-up die-bonding to a predetermined position of 30. After each chip is fixed to the package 30 in this manner, the pads on the primary side provided on each chip are electrically bonded by wire bonding to the pads on the secondary side provided in the wiring circuit on the package 30. Connections are made.

Reference numeral 12a is a primary side pad provided in the error amplification IC 12, and is connected to a secondary side pad 30b provided on the wiring circuit of the package 30 by wire bonding. Reference numeral 16a denotes a primary side pad of the switch driving IC 16, which is wire-bonded to the secondary side pad 30c of the package 30, similarly to the error amplification IC12. In the thin film transmission transformer 20, since the bumps 21'a are already connected to the IC12 side for the error amplification circuit via the pads 30a on the package 30, only the pads 21a are the IC16 side for the switch drive and the secondary side. Wire bonding is performed via the pad 30d.

The control circuit thus completely electrically connected is finally covered with the cap 31 and sealed.

FIG. 5 is an exploded perspective view of a control circuit which is another embodiment of the stabilized DC power supply device of the present invention. 32 is the first
In the figure, a ceramic substrate made of the same material as that used for the thin film transmission transformer is used, and has a substantially rectangular shape with a width W and a length K. On both sides of the areas A and B of the ceramic substrate 32,
A silicon single crystal is formed by SOS (silicon on sapphire) growth, and an IC for error amplification is formed on the back surface of the A region.
12 'is provided, and the switch driving IC is on the surface of the B area.
16 are provided. The C region is a portion where the silicon single crystal is not formed, and the primary coil 21 'and the secondary coil 21 of the thin film transmission transformer 20 are formed on each surface of this region. The primary coil 21 'is connected to the error amplifying IC 12' by a thin film conductor pattern (not shown), and the secondary coil 21 is connected to the switch driving IC 16 by a thin film conductor pattern (not shown).

Reference numeral 12'a is a bump for connecting the IC 12 'for error amplification to an external circuit, and is bonded to a pad 33a in the circuit provided on the package 33. 16a for switch drive
It is a primary side pad for connecting the IC 16 to an external circuit, and is connected by wire bonding to a secondary side pad 33b on the package 33.

In this way, the control circuit electrically connected to the external circuit is covered with the cap 31 and then sealed.

<Effects of Device> As described in detail above, the control circuit of the present invention is a hybrid in which the transmission transformer in the control circuit is thinned and the error amplifier circuit and the switch drive circuit are also integrated into an IC. Can be miniaturized and functionalized.

In addition, on each surface of one ceramic substrate, IC
Since the thin film transmission transformer and the
The number of parts is small and the mounting workability is good.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the overall structure of a DC stabilized power supply device of the present invention, and FIG. 2 is a block diagram of a thin film transmission transformer used in a control circuit of the DC stabilized power supply device of the present invention.
(A) is a plan view, (B) is a sectional view taken along the line AA ', FIG. 3 is a sectional view for explaining the loss of magnetic flux, and FIG. 4 is an exploded view of the control circuit of the DC stabilized power supply device of the present invention. FIG. 5 is an exploded perspective view of a control circuit according to another embodiment, and FIG. 6 is a configuration block diagram of a conventional DC stabilized power supply device. 12 ... IC for error amplification, 16 ... IC for driving switch, 20 ... Thin film transmission transformer, 21, 21 '... Thin film coil (primary and secondary coil), 23, 23' ... Insulating layer, 24, 24 '... Magnetic thin film, 3
0, 33 ... Package.

Claims (2)

[Scope of utility model registration request] 1. A switch element turns on / off an input DC voltage.
Turn off to apply to the primary winding of the transformer, rectify and smooth the alternating signal induced in the secondary winding, and turn on the switching element to maintain the output DC voltage of the DC / DC converter that is supplied to the load constant. In a control circuit for controlling ON / OFF, an error amplification IC that extracts an error amplification signal obtained by comparing the output voltage with a reference voltage as a pulse signal, and the pulse signal is supplied to a primary coil, and a secondary coil A thin film transmission transformer in which an output signal is induced in a thin film is formed on a ceramic, and a switch drive for controlling ON / OFF of the switch by receiving a pulsed signal obtained from the secondary side of the thin film transmission transformer. IC, the first coil of the thin film transmission transformer and the error amplification
A control comprising: a circuit for connecting an IC circuit through a thin film circuit, and a package for connecting a second coil of the thin film transmission transformer and a circuit for the switch driving IC through the thin film circuit. circuit. 2. An input DC voltage is turned on / off by a switch element.
Turn off to apply to the primary winding of the transformer, rectify and smooth the alternating signal induced in the secondary winding, and turn on the switching element to maintain the output DC voltage of the DC / DC converter that is supplied to the load constant. In a control circuit for controlling ON / OFF, an error amplification IC for extracting an error amplification signal obtained by comparing the output voltage with a reference voltage as a pulse signal and the pulse signal are supplied to the primary coil on one surface. A thin film transmission transformer is provided, and a switch for driving the secondary side coil of the thin film transmission transformer and a pulse-shaped signal obtained from the secondary side coil on the other surface to control ON / OFF of the switch. A circuit board of the error amplification IC is connected to an external circuit through a thin film circuit, and a circuit board of the switch driving IC is connected to the external circuit through the thin film circuit. Control circuit is characterized in that anda package to be connected.