JPH07254719A - Semiconductor device and method for adjusting element value of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent an increase in the number of external terminals in a semiconductor device in which the operation of a built-in adjusting element can be adjusted through Zener zap trimming. CONSTITUTION:A plurality of Zener diodes ZD are connected in series in a copolar direction, and the Zener diodes ZD have individual PN junction areas respectively, further adjusting elements R are connected in parallel to the Zener diodes ZD respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a function of adjusting the operation of an adjusting element such as a built-in resistor.

Generally, a general-purpose IC cannot be as highly integrated as a custom IC limited to a specific application. In such a general-purpose IC, an external resistor is connected to ensure versatility. However, in order to further improve versatility, an external resistor is incorporated and a terminal is used. It is necessary to reduce the number. The resistance of the built-in resistor needs to be adjustable in order to ensure the versatility of the IC.

[0003]

2. Description of the Related Art A conventional example of a resistor incorporated in a general-purpose IC and having a resistance value adjustable by Zener zap trimming will be described with reference to FIG.

A resistor R1 connected in series between terminals X and Y
To R3 are zener diodes ZD1 to ZD, respectively.
3 are connected in parallel. The anode and cathode of the Zener diode ZD1 are connected to the external terminals Z0 and Z1. The anode and cathode of the Zener diode ZD2 are connected to the external terminals Z1 and Z2. The Zener diode ZD3 has an anode and a cathode connected to the external terminals Z2 and Z2.
It is connected to Z3.

As described above, the resistance values of the resistors R1 to R3 connected between the terminals X and Y are the zener diodes ZD1 to ZD1.
Depending on whether or not the ZD3 is destroyed to bring it into a short-circuited state, adjustment can be made in eight ways as shown in FIG.

In FIG. 7, a circle indicates a state where the Zener diode is not destroyed, and a cross indicates a case where the Zener diode is destroyed by an overcurrent in the reverse direction to make a short circuit state.

When the Zener diodes ZD1 to ZD3 are not destroyed, the resistance value between the terminals X and Y is R1 +.
It becomes R2 + R3. When a breakdown current is passed from the external terminals Z0 and Z1 to the Zener diode ZD1 and only the Zener diode ZD1 is destroyed to bring it into a short-circuited state, the resistance value between the terminals X and Y becomes R1 + R2.

Similarly, a Zener diode ZD
When all of 1 to ZD3 are destroyed, the resistance value between the terminals X and Y becomes almost 0Ω. In this way, the resistance value between the terminals X and Y can be adjusted in eight ways.

[0009]

In the structure for adjusting the resistance values of the resistors R1 to R3 connected in series as described above,
Four external terminals Z0 for destroying the Zener diodes ZD1 to ZD3 connected in parallel to the resistors R1 to R3
~ Z3 is required.

Further, in order to destroy the Zener diode connected in parallel to the n resistors, n + 1 external terminals are required. Therefore, there is a problem in that the number of external terminals increases in order to form a resistor whose resistance value can be adjusted.

An object of the present invention is to prevent an increase in the number of external terminals of a semiconductor device in which the operation of a built-in adjusting element can be adjusted by Zener zap trimming.

[0012]

FIG. 1 is a diagram for explaining the principle of the present invention. That is, a plurality of Zener diodes ZD are connected in series in the same polarity direction, each Zener diode ZD has a separate PN junction area, and the adjusting element R is connected in parallel to the Zener diode ZD.

Further, as shown in FIG. 2, the Zener diode ZD is connected in parallel with resistors R as the adjusting elements. Further, the PN junction areas of the plurality of Zener diodes ZD11 to ZD17 connected in series are sequentially increased from one Zener diode ZD11 to the other Zener diode ZD17.

Resistors R31 to R34 are connected in parallel between the terminals to which the cathodes of a plurality of Zener diodes ZD31 to ZD34 connected in series are connected and the anodes of the Zener diodes ZD31 to ZD34. The Zener diodes ZD31 to ZD
The PN junction area of D34 is from the Zener diode ZD31 connected to the terminal to the other Zener diode Z.
It is gradually reduced toward D34.

Further, as shown in FIG. 4, a plurality of Zener diodes ZD21 to ZD25 are connected in series in the same polarity direction, the Zener diodes ZD21 to ZD25 have respective PN junction areas, and the Zener diodes ZD21 to ZD21 to A resistance value adjusting circuit is formed by connecting the resistors R21 to R25 in parallel to the ZD25, and the measured voltage VR generated by dividing the fixed resistance R and the resistance by the resistance value adjusting circuit and the reference voltage. The voltage drop of the measured voltage VR is detected by comparing Vref with the comparator 2.

Further, a plurality of Zener diodes are connected in series in the same polarity direction, each Zener diode has a separate PN junction area, and an adjusting element is connected in parallel to the Zener diode, and the plurality of Zener diodes are connected. The element value of the adjusting element is adjusted by adjusting the reverse current flowing through the device and adjusting the number of the Zener diodes that are destroyed by the reverse current and are in a short-circuit state.

[0017]

By supplying a reverse current to the Zener diodes ZD connected in series and adjusting the current value of the reverse current, an arbitrary number of Zener diodes ZD are destroyed and short-circuited. Then, the adjusting element R connected in parallel with the destroyed Zener diode is short-circuited.

In FIG. 2, by destroying an arbitrary number of Zener diodes ZD, the resistance value of the resistors connected in parallel to the plurality of Zener diodes ZD is adjusted. Further, in FIG. 2, when the reverse currents flowing through the plurality of Zener diodes ZD11 to ZD17 connected in series are sequentially increased, the Zener diodes ZD11 to ZD are generated.
17 is sequentially destroyed from one Zener diode ZD11 toward the other Zener diode ZD17.

Further, in FIG. 5, if the Zener diodes ZD31 to ZD34 are sequentially broken down, the resistors R31 to R are formed.
34 are sequentially connected in parallel. Also, in FIG. 4, if the Zener diodes ZD21 to ZD25 are destroyed in an arbitrary number and the resistance values of the resistors R21 to R25 are adjusted, the measured voltage VR generated by the voltage division between the fixed resistor R and the resistors R21 to R25 becomes The measured voltage VR is adjusted and the reference voltage Vref is compared by the comparator 2.

[0020]

2 and 3 show a first embodiment embodying the present invention. 7 between terminals A and B connected to the external terminal
The resistors R11 to R17 having the same resistance value are connected in series, and the Zener diodes ZD11 to ZD17 are connected in parallel to the resistors R11 to R17, respectively.

Zener diodes ZD11 to ZD1
The junction areas of the PN junction portions of No. 7 are different from each other, and are set to increase sequentially from the Zener diode ZD11 to the same ZD17.

Therefore, each Zener diode ZD11 ...
The reverse current value for destroying ZD17 is set to increase sequentially from Zener diode ZD11 to ZD17.

The resistors R11 to R17 connected between the terminals A and B as described above are adjusted by adjusting the value of the current flowing from the terminal B to the terminal A to adjust the number of zener diodes to be destroyed. The resistance value is adjusted in eight ways as shown in FIG.

In FIG. 3, ◯ indicates a state in which the Zener diode is not destroyed, and X indicates a case in which the Zener diode is destroyed by an overcurrent in the reverse direction to make a short circuit state.

When the Zener diodes ZD11 to ZD17 are not destroyed, the resistance value between the terminals A and B is the resistance R1.
It becomes the sum of the resistance values of 1 to R17. At this time, terminals A and B
A voltage equal to or lower than the breakdown voltage of the Zener diodes ZD11 to ZD17 is applied between them for use.

When the short-circuit current flowing from the terminal B to the terminal A is gradually increased, first, the Zener diode ZD11 is destroyed to be in a short-circuit state. In this state, the resistance value between the terminals A and B is the sum of the resistance values of the resistors R12 to R17.

Further, when the short-circuit current flowing from the terminal B to the terminal A is further increased, the Zener diode ZD12 is destroyed and becomes a short-circuit state. In this state, the resistance value between the terminals A and B is the sum of the resistance values of the resistors R13 to R17.

When the short-circuit current is increased in this way, the Zener diodes ZD11 to ZD17 are all destroyed in due course, and the resistance value between the terminals A and B becomes almost 0Ω. As described above, in the resistance value adjusting circuit, the terminals A,
By adjusting the value of the current supplied between B, it is possible to destroy the arbitrary number of zener diodes among the zener diodes ZD11 to ZD17 and adjust the resistance value.

Therefore, the resistance value can be adjusted by the two external terminals connected to the terminals A and B regardless of the number of Zener diodes. Further, although the Zener diodes ZD11 to ZD17 are arranged according to the size of the junction area of the PN junction in the above-mentioned embodiment, the connecting order may be arbitrary.

An example of using the resistance adjusting circuit as described above in a voltage drop detecting circuit incorporated in a semiconductor device is shown in FIG.
Shown in. The battery voltage V is applied to the voltage regulator circuit 1.
BATT is supplied, and the voltage regulator circuit 1 outputs a constant voltage power supply Vcc based on the battery voltage VBATT.

The negative input terminal of the comparator 2 is
The detection voltage setting terminal TR is connected to the detection voltage setting terminal TR, and the detection voltage setting terminal TR is connected to the power source Vcc via the resistor R.
Is connected to the ground GND via R21. Also,
The detection voltage setting terminal TR is connected to an external terminal.

Zener diodes ZD25 to ZD21 are connected in parallel to the resistors R25 to R21, respectively. The Zener diodes ZD25 to ZD21 have the same PN junction area as the Zener diodes ZD25 to ZD25.
It is set so as to gradually decrease toward 21.

The reference voltage Vref is input to the positive input terminal of the comparator 2. Then, the comparator 2 outputs an H level signal to the reset output signal processing circuit 3 when the potential of the detection voltage setting terminal TR becomes lower than the reference voltage Vref.

The reset output signal processing circuit 3 outputs the reset signal RS to another internal circuit based on the output signal of the comparator 2. In the voltage drop detection circuit configured as described above, the detection voltage VR set at the detection voltage setting terminal TR is set to the power source Vcc by the resistor R and the resistors R25 to R21.
It is set by partial pressure with and.

When the power source Vcc drops due to the drop of the battery voltage VBATT or the like, the detection voltage VR drops. Then, when the detection voltage VR becomes lower than the reference voltage Vref, the reset output signal processing circuit 3 outputs the reset signal RS to another internal circuit.

In such a voltage drop detection circuit, the detection voltage VR can be adjusted by breaking any number of the Zener diodes ZD25 to ZD21 to make them short-circuited. To adjust the detection voltage VR, a Zener diode Z is provided between the detection voltage setting terminal VR and the ground GND.
A breakdown current for destroying D25 to ZD21 is passed. Then, the detection voltage VR can be adjusted by adjusting the breakdown current value and selecting the number of Zener diodes to be destroyed.

FIG. 5 shows a resistance value adjusting circuit according to a second embodiment of the present invention. Zener diodes ZD34 to ZD31 are connected in series between the terminals C and D. The Zener diodes ZD34 to ZD31 are set so that the PN junction area gradually increases from the Zener diode ZD34 toward the ZD31.

A resistor R31 is connected in parallel to the Zener diode ZD31, and the Zener diode ZD31 is connected.
A resistor R32 is connected to 31 and ZD32 in parallel. A resistor R33 is connected in parallel to the Zener diodes ZD31, ZD32, ZD33, and a resistor R is provided for the Zener diodes ZD31, ZD32, ZD33, ZD34.
34 are connected in parallel. The resistors R31 to R34 have the same resistance value.

In the resistance value adjusting circuit configured as described above, only the resistor R34 is connected between the terminals C and D when the Zener diodes ZD31 to ZD34 are not destroyed.

When the breakdown current flowing from the terminal D to the terminal C is sequentially increased, first, the Zener diode Z
D34 is destroyed and short-circuited. Then, the resistance value between the terminals C and D becomes a combined resistance value in which the resistors R33 and R34 are connected in parallel.

When the breakdown current flowing from the terminal D to the terminal C is further increased, the Zener diode ZD
33 is destroyed and short-circuited. Then, terminals C,
The resistance value between D is a combined resistance value in which the resistors R32, R33, and R34 are connected in parallel.

When the breakdown current flowing from the terminal D to the terminal C is further increased, the Zener diode ZD
32 is destroyed and short-circuited. Then, terminals C,
The resistance value between D is a combined resistance value in which the resistors R31, R32, R33, and R34 are connected in parallel.

Therefore, the resistance value between the terminals C and D can be adjusted by adjusting the breakdown current flowing between the terminals C and D. Although the circuits for adjusting the resistance value by the Zener zap trimming are shown in the first and second embodiments, the operation of the elements other than the resistance, for example, the operation of the capacitance, other unit circuits, etc., can be performed by the Zener zap. It is also possible to adopt a configuration in which adjustment is performed by trimming.

The technical ideas other than the claims that can be understood from the above-described embodiments will be described below along with their effects. (1) In Claim 1, the Zener diode (Z
In D), capacitors were connected in parallel as the adjusting elements. The capacitance value can be adjusted by breaking an arbitrary number of Zener diodes to make them short-circuited.

(2) In claim 1, unit circuits are connected in parallel to the Zener diode (ZD) as the adjusting elements. The operation of the unit circuit can be adjusted by breaking an arbitrary number of Zener diodes to make them short-circuited.

(3) In claim 1, one end of each of a plurality of resistors is connected to a cathode end of the Zener diode (ZD) array, and the other end of the resistor is connected to an anode of each Zener diode. It is possible to set a combined resistance value of an arbitrary number of resistors by breaking an arbitrary number of Zener diodes into a short circuit state.

(4) A semiconductor integrated circuit comprising the semiconductor device according to claim 1, wherein the anode and cathode ends of the Zener diode array are connected to external terminals. It is possible to adjust the characteristics of the internal circuit by causing a breakdown current to flow from the external terminal to the Zener diode array and destroying an arbitrary number of Zener diodes.

[0048]

As described in detail above, according to the present invention, it is possible to prevent an increase in the number of external terminals of a semiconductor device in which the resistance value of a built-in resistor can be adjusted by Chener zap trimming.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a circuit diagram showing a first embodiment.

FIG. 3 is an explanatory diagram showing an example of resistance value adjustment according to the first embodiment.

FIG. 4 is a circuit diagram showing a usage example of the first embodiment.

FIG. 5 is a circuit diagram showing a second embodiment.

FIG. 6 is a circuit diagram showing a conventional example.

FIG. 7 is an explanatory diagram showing a resistance value adjustment example of a conventional example.

[Explanation of symbols]

 ZD Zener diode R adjustment element

Claims (6)

[Claims] 1. A plurality of Zener diodes (ZD) are connected in series in the same polarity direction, and the Zener diodes (ZD) are connected in series.
D) has a separate PN junction area, and the adjusting element (R) is connected in parallel to the Zener diode (ZD). 2. The semiconductor device according to claim 1, wherein a resistor (R) is connected in parallel to each of the zener diodes (ZD) as the adjusting element. 3. The PN junction areas of the plurality of Zener diodes (ZD11 to ZD17) connected in series are sequentially increased from one Zener diode (ZD11) to the other Zener diode (ZD17). The semiconductor device according to claim 1. 4. A terminal to which cathodes of the plurality of Zener diodes (ZD31 to ZD34) connected in series are connected, and each Zener diode (ZD31 to ZD).
34) to the anode (R31-R31).
R34) are connected in parallel, and the PN junction area of each of the Zener diodes (ZD31 to ZD34) is sequentially reduced from the Zener diode (ZD31) connected to the terminal to the other Zener diode (ZD34). The semiconductor device according to claim 1, wherein the semiconductor device is a semiconductor device. 5. A plurality of Zener diodes (ZD) are connected in series in the same polarity direction, and the Zener diodes (ZD) are connected in series.
D) each have a separate PN junction area, and a resistance adjusting circuit is formed by connecting the adjusting element (R) in parallel to the Zener diode (ZD) to form a fixed resistance and a resistance by the resistance adjusting circuit. A voltage drop detection circuit for detecting a voltage drop of the measured voltage by comparing with a comparator a measured voltage generated by the divided voltage. 6. A plurality of Zener diodes (ZD) are connected in series in the same polarity direction, and the Zener diodes (ZD) are connected in series.
D) each have a separate PN junction area, the adjusting element (R) is connected in parallel to the Zener diode (ZD), and the reverse current flowing through the plurality of Zener diodes (ZD) is adjusted, A device value adjusting method for a semiconductor device, wherein the device value of the adjusting device (R) is adjusted by adjusting the number of the Zener diodes (ZD) that are destroyed by a reverse current and are in a short circuit state.