JP3435806B2 - Infrared remote control receiving IC - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an infrared remote control receiving IC.
The present invention relates to a circuit system for stabilizing the output in the above, and an infrared remote control receiving IC with an improved ground line. 2. Description of the Related Art In recent years, general-purpose infrared remote control receiving ICs widely used in home AV equipment and general electric equipment are roughly classified into a built-in type having a light receiving element such as a PIN photodiode or the like. There is an external type in which a light receiving element is externally mounted. In this example, the external type will be described. A conventional infrared remote control receiving IC will be described with reference to FIGS. 3 is a block diagram showing a conventional infrared remote control receiving IC, FIG. 4 is a diagram showing an output circuit of the conventional infrared remote control receiving IC, and FIG. 5 is a prior art IC pattern layout. It is. First, the configuration of a conventional infrared remote control receiving IC will be described with reference to FIG. FIG. 3 is a block diagram showing a conventional infrared remote control receiving IC.
Generally, an infrared remote control receiving IC has an input terminal 3, an output terminal 4, a ground terminal 5 (GND, hereinafter simply referred to as "ground"), a power terminal 6 (Vcc, hereinafter simply "power").
To be written). Reference numeral 1 denotes the inside of the infrared remote control receiving IC, and an input stage 7 for processing a signal input from an input terminal 3 and a signal processing unit 8 (BPF,
A decoder, an integrator), an output stage 9 including an output circuit section, and the like. Next, the operation of a block diagram showing a conventional infrared remote control receiving IC having such a configuration will be described. First, a signal from the light receiving element 2 such as a PIN photodiode is input to the input stage 7 via the input terminal 3.
The input stage 7 further performs current-to-voltage conversion on the input signal obtained by current-converting the light from the light by the light receiving element 2 to perform pre-stage amplification.
When strong light is incident on the IN photodiode or the like and the photocurrent increases, the gain is automatically reduced to prevent the circuit from exceeding the allowable range of the circuit. Signal processing unit 8
Is a BPF for removing noise components from a carrier wave,
It is composed of a demodulator that separates a carrier and reproduces a required signal, an integrator that converts the signal into a DC level, and the like. The part related to the present invention is an output stage 9 including an output circuit unit, and its operation is to compare the signal waves output from the signal processing unit (BPF, decoder, integrator) 8 with a certain threshold value. , Which are output through the output terminal 4 as pulses of a practical level. [0005] This output is generally a PPM (Pulse
The signal is output in the Position Modulation (Position Modulation) method, and “1” and “0” are defined by the pulse interval (time). As an example, a pulse has a certain interval (Tp
= 1.2 msec), it is determined to be “1”, and when the pulse is half (Tp = 0.6 msec), it is determined to be “0”. The signals of “1” and “0” are defined. 15
It is assembled and output as bit serial data (continuous signal). The pulse voltage is normally Low (around 0 volt, hereinafter simply referred to as “Low”) and High (5
This output transistor is configured to reciprocate between the vicinity of a volt, and hereinafter simply referred to as “High”.
A rectangular wave pulse between ow and High is a portion that is continuously output with a large operating current. The configuration of the output circuit section 10 will be described with reference to FIG. FIG. 4 is a diagram showing an output circuit of a conventional infrared remote control receiving IC, in which a transistor Tr is inputted from an input 14.
And the emitter of Tr is connected to a power supply at 6A. The collector of Tr is a resistor 1R, 2R
And connected to the base C of the transistor Tr. The resistor 2R is connected to ground at 5A, and the emitter of Tr is connected to ground at 5B. Tr Collector D
Is connected to the power supply at 6B via 3R and at the same time to the output 15. Parasitic transistor Tr described later
Represents the base connected to the collector D of the transistor Tr and the parasitic transistor T
The emitter of r is connected to the base C of Tr, and the collector of the parasitic transistor Tr is connected to ground at 5C. Next, the operation of the output circuit section 10 will be specifically described with reference to FIG. The operation state of the output circuit unit 10 is defined as active low, that is, “1” or “0” is determined based on the length of the low interval (time). Less than,
The operation state is defined as Low and the steady state is High. In the steady state High, the transistors Tr, Tr
In the "F" state, the output 15 is pulled up by the resistor 3R and is fixed near 5 volts of the power supply 6B. Next, in the operation state Low, the transistor Tr is turned “ON” and the operation current 11I flows, whereby the transistor Tr is turned “ON”, the operation current 12I flows, and the output 15 is fixed at about 0.2 volt. You. At this time, the base (potential) C of the transistor Tr becomes about 0.7 volt,
(Potential) D, that is, the output 15 is about 0.2 volts, so that a parasitic transistor (which is a part of a non-existent apparent transistor) Tr is generated between the base C and the collector D of the transistor Tr. . The parasitic transistor Tr is turned “ON”, and the operating current 13I flows into the substrate (semiconductor substrate, hereinafter simply referred to as “substrate”). This operation occurs, for example, every time the 15-bit rectangular wave serial data of the 15-bit configuration is continuously output, and when a low impedance state exists between the output 15 and the power supply 6B, the circuit In this case, an excessively large operating current flows than in the predetermined initial setting state, and this phenomenon causes various problems as described later. Next, the configuration and operation of the ground line pattern will be described with reference to FIG. FIG. 5 shows a prior art IC.
It is a pattern arrangement diagram. Reference numerals 21, 22, and 23 denote remaining circuit blocks constituting an IC, reference numerals 24, 25, and 26 denote portions where the ground of the remaining circuit block is connected to the ground line 20, and 27 denotes a portion where the output circuit section 10 2 shows a portion connected to the ground line 20. 28
Indicates connection portions to the IC substrate. As shown, in the example of the prior art IC pattern layout diagram, the ground 27 of the output circuit section of the output circuit section 10 with a large operating current and the grounds 24, 25, 26 are all wired to the common ground line 20 and are further connected to the substrate via 28. Therefore, the grounds 24, 25, 26 of the residual circuit block and the ground 27 of the output circuit section
And a small resistance between them, which becomes a common impedance, and a large operating current of the output circuit section 10 flows through the common impedance, so that the potential of the ground line 20 rises. To the remaining circuit blocks 21, 22, and 23 connected to the grounds 24, 25, and 26, and adversely affects the circuit operation. [0010] However, in the output circuit system of the conventional infrared remote control receiver IC shown in FIG. 4, a parasitic transistor Tr is generated between the base C and the collector D of the transistor Tr. Therefore, for example, when the 15-bit rectangular wave serial data is continuously output, the parasitic transistor Tr is intermittently turned on, and the operating current 13I flows into the substrate. Further, when a low impedance state exists between the output 15 and the power supply 6B, an excessively large operating current flows than in the initial setting state predetermined by the circuit. These operations are performed by the output circuit 1
There is a disadvantage that causes a malfunction of 0. Further, in the ground line structure as shown in the prior art IC pattern layout diagram shown in FIG. 5, the ground 27 and the remaining circuit blocks 21, 22, 23 of the output circuit section of the output circuit section 10 with a large operating current. Since the grounds 24, 25, and 26 of the remaining circuit blocks are on the same ground line 20 and are further connected to the IC substrate through the connection portion 28 to the IC substrate, the ground flows into the IC substrate. The large operating current of the output circuit unit 10 is:
Feedback is caused by the common impedance, which electrically excites the input stage 7 or the entire circuit, and has the drawback that noise is mixed into the output waveform, the entire circuit malfunctions, and oscillation occurs. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, and an object of the present invention is to provide an infrared remote control receiving IC capable of performing stable output. [0012] In order to solve the above-mentioned problems, the present invention relates to a receiving IC for an infrared remote control having an output circuit section comprising an output transistor having a collector as an output. A transistor for clamping the collector potential of the output transistor to the base potential or
A diode and a base / collector of the output transistor
The above problem was solved by providing a resistor arranged so that the data potentials are substantially the same, thereby preventing a malfunction of the parasitic transistor. [0013] Furthermore, a first ground line connected to the IC substrate and a second ground line formed by extending a dedicated wiring material such as aluminum are provided to generate a large operating current during switching operation. The ground line of the output transistor to be connected is concentratedly connected to a second ground line formed by extending a dedicated wiring material such as aluminum , and
The second ground line of the IC and the IC substrate are not connected.
The above problem was solved by adopting a method of preventing the influence on other circuits. In a receiving IC for an infrared remote control provided with an output circuit section constituted by an output transistor having a collector as an output, a transistor or a diode for clamping a collector potential of the output transistor to a base potential.
And the base / collector potential of the output transistor is
By providing the resistors arranged so as to be substantially the same, it is possible to eliminate the influence of the parasitic transistor generated between the base and the collector of the output transistor, prevent malfunction of the circuit section, and obtain a stable output. It becomes possible. [0015] generating a first ground line connected to the IC substrate, it comprises a second ground line constituted by extending a special wiring material such as aluminum, a large operating current during switching operation The ground line of the output transistor to be connected is connected to a second ground line formed by extending a dedicated wiring material such as aluminum, and the second ground line is connected to the second ground line.
By disconnecting the IC and the IC substrate, it is possible to prevent the influence on other circuits caused by the common impedance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An infrared remote control receiving IC according to the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing an output circuit of an infrared remote control receiving IC of the present invention.
FIG. 2 is a plan view showing an example of an IC pattern arrangement according to the present invention, and reference numeral 30 denotes an output circuit unit according to the present invention. FIG. 4 shows an output circuit of a conventional infrared remote control receiving IC.
Also, the portions having the same functions as those of the IC pattern layout diagram 5 of the related art are denoted by the same reference numerals, and description of the configuration and the like is omitted. First, the structure of the output circuit section 30 of the present invention will be described with reference to FIG. The collector of the transistor Tr is connected to the ground 5A via the resistors 35R, 36R and 37R. A is a transistor T between the resistors 35R and 36R.
The emitter B of the transistor Tr is connected to the base C of the transistor Tr between the resistors 36R and 37R, the emitter is connected to the ground 5B, the collector D is connected to the collector and base of the transistor Tr, and connected to the power supply 6B via the resistor 3R. Furthermore, it is connected to the output 15. Next, the specific operation of the output circuit section 30 of the present invention will be described with reference to FIG. In the output circuit section 30 of the present invention, in the steady state High, the transistor Tr, the transistor Tr, and the transistor Tr are all in the “OFF” state, and the output 15 is held by the power supply 6B by the pull-up resistor 3R. Operating state Lo
In w, the transistor Tr is turned “ON” and the current 11I flows. As a result, the potentials at points A and B increase, and the transistor Tr turns “ON”. The transistor Tr is "O
N ", the current 12I flows and the output 15 (Tr
Collector D) drops to 0.2 volts. Since the potential at the point A is increasing and the output 15 is decreasing, when the potential difference between the point A and the output 15 becomes about 0.7 volt, the newly provided transistor Tr is turned “ON”, and the potential from the point A is increased. VBE
The output 15 is fixed at a low potential (about 0.6 volts).
The transistor Tr is illustrated as a PNP transistor, but may be an NPN transistor or a diode. The resistor 36R is determined in advance so that the potential at the point B and the potential of the output 15 are substantially the same. The configuration of the output circuit section 30 of the present invention allows the parasitic transistor shown in the prior art output circuit section 10 to be formed. Tr is stably maintained in the “OFF” state, and the output transistor Tr shown in the output circuit unit 30 of the present invention maintains a stable operation. Further, the configuration and operation of the ground line pattern of the present invention will be described with reference to FIG. FIG. 2 is an IC pattern layout diagram of the present invention, in which a first ground line 41 connected to an IC substrate and the first ground line 4 are connected.
1 and a second grounding line 42 extending from a dedicated wiring material such as aluminum is newly provided. Output circuit section 3 of the present invention that generates a large operating current during switching operation
0, ground 2 of the output circuit section of the present invention of the output circuit section II43
9. The ground 44 of the output circuit section II is connected to the second ground line 42, and includes the input stage 7 and the like constituting an IC.
The grounds 24 and 25 of the remaining circuit blocks of the remaining circuit blocks 21 and 22 are connected to the first ground line 41 connected to the IC substrate, so that the ground lines are separated for each application. The present invention is not limited to the above-described embodiment, but can adopt various embodiments, and it is needless to say that the present invention can be used for a bipolar power semiconductor integrated circuit device with current amplification. According to the configuration of the output circuit section of the present invention, even when serial data of a rectangular wave is continuously output, the parasitic transistor is turned on and off intermittently. Therefore, the circuit is completely and stably kept in the "OFF" state, thereby preventing malfunction and oscillation of the circuit. In addition, even when a low impedance state exists between the output and the power supply, the operation of the newly provided transistor prevents an excessive operation current from flowing in the initial setting state, thereby preventing a malfunction of the output circuit section. it can. A ground for the output circuit with a large operating current;
Since the ground of the remaining circuit block including the input stage is completely separated for each application, the large operating current of the output circuit flowing into the IC substrate is fed back by the common impedance, and the input stage or the entire circuit is electrically excited. Disappeared, and the ground noise was reduced. In addition, it is possible to prevent noise from entering the output waveform and oscillation,
It is possible to obtain a stable output. As described above, according to the infrared remote control receiving IC of the present invention, a stable output can be always obtained even with respect to various fluctuation factors.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing an output circuit of an infrared remote control receiving IC of the present invention. FIG. 2 is a plan view showing an example of an IC pattern arrangement according to the present invention. FIG. 3 is a block diagram showing a conventional infrared remote control receiving IC. FIG. 4 is a diagram showing an output circuit of a conventional infrared remote control receiving IC. FIG. 5 is a prior art IC pattern layout. [Description of Signs] 1 Internal part of infrared remote control receiving IC 2 Light receiving element 3 Input terminal 4 Output terminal 5 GND (earth ground terminal) 6 Vcc (power supply terminal) 7 Input stage 8 Signal processing unit 9 Output stage 10 Output circuit unit 14 Input REFERENCE SIGNS LIST 15 output 20 ground line 21 residual circuit block 24 residual circuit block ground 27 output circuit part ground 28 connection part to IC substrate (semiconductor substrate) 29 ground of output circuit part of the present invention 30 output circuit part 41 of the present invention First ground line 42 Second ground line 1R to 3R Resistance 35R to 37R Resistance 11I to 13I Current

Claims (1)

(57) Claims 1. In a receiving amplifier IC for an infrared remote control provided with an output circuit section including an output transistor, a transistor or a transistor for clamping a collector potential of the output transistor to a base potential. The output transistor has a base / collector potential substantially equal to that of the output transistor.
And a first ground line connected to the semiconductor substrate via an isolation region.
And a second ground line formed by extending a dedicated wiring material.
And a ground line for the output transistor is connected to the second ground line.
And the second ground line
And an infrared remote control receiving IC, wherein the infrared remote control receiving IC is not connected to the semiconductor substrate .