KR101794871B1 - Trimming circuit and controlling method thereof - Google Patents

Abstract

The trimming circuit comprises a first switch comprising a first switch connected in series between a first node and a second node and a first current source of a first current level and a second switch connected in series between the second node and a second switch And a second current source of a second current level, the second arm being in parallel with the first arm and a third switch connected in series between the first node and the second node and a third current source of a third current level, And a third arm in parallel with the first arm and the second arm, wherein the output of the second node in accordance with on / off states of the first switch, the second switch, and the third switch A current level is determined, and the first current level and the third current level are equal to each other.

Description

[0001] TRIMMING CIRCUIT AND CONTROLLING METHOD THEREOF [0002]

The present invention relates to a trimming circuit and a control method thereof.

The trimming circuit is mainly used in a semiconductor integrated circuit and is used to control a change in an output value due to a process error or an error generated in the process of manufacturing a semiconductor integrated circuit. In particular, in the case of semiconductor integrated circuits used in automotive electronic components, the functional safety standards such as ISO 26262 must be met for the safety of the driver.

3 is a diagram showing a conventional trimming circuit.

Referring to FIG. 3, the trimming circuit 30 includes a switch and a plurality of arms in which one current source constitutes one arm, and the plurality of arms are connected in parallel with each other.

The current sources 311, 321, and 331 have different current levels. For example, the current source 311 has a current level I _3, the current source 321 has a current level of 2I _3, the current source 331 has a current level 4I _3.

Switch _{(SW 3_1, SW 3_2, SW} 3_3) is the output current of the control signal _{(S 3_1, S 3_2, S} 3_3) on the OFF state is controlled, and the output current (I _{3_out)} by the combination of the on and off states by The level is determined.

4 is a diagram for explaining an output current level of an output current of a conventional trimming circuit.

Referring to FIG. 4, the graph 40 shows the value of the control signal S ₃ as the horizontal axis and the output current level of the output current I _{3_out} as the vertical axis. The control signal (S ₃₎ is the value of the control signal (S _{3_1)} the second bit, the control signal (S _{3_3)} to the value of the first bit, the control signal (S _{3_2)} value of can be expressed by the three bits .

When the control signal S ₃ is "000", all the switches SW 3 _{_ 1} , SW 3 _{_ 2} and SW 3 _{_} 3 are in the OFF state and therefore no current can flow in all the current sources 311, 321, _{3_out} ), the output current level is zero. If the control signal (S ₃₎ "001", the switch (SW _{3_2,} SW _{3_3)} in an off state and the switch (SW _{3_1)} in an on state, and therefore, because only the current source 311 is conductive, the output current (I _{3_out)} output current level is equal to the current level I _3. Output current level in the same manner trim the output current (I _{3_out)} of the circuit 30 includes eight current levels _{0, I 3, 2I 3,} 3I 3, 4I 3, 5I 3, be selected as one of the 6I _3, 7I ₃ .

The conventional trimming circuit 30 has an advantage that a maximum number of output current levels of 2 ⁿ can be produced by using n switches. However, a harsh environment as automotive parts as described above, when a fault or short-circuit switch (SW _{3_2)} under (high temperature and pressure of the environment), the output current level of four current levels _{0, I 3, 4I 3,} 5I 3 is There is a problem that can not be. That is, even if only one switch fails, there is a problem that the expressible output current level is reduced to half. In such cases, a simple malfunction of the vehicle's electrical components can pose a threat to the life of the driver, such as a sudden acceleration or abnormal operation of the engine.

The technical problem to be solved is to provide a trimming circuit which satisfies the functional safety standard of ISO 26262, capable of outputting an output current at a desired output current level even when a switch fails, and a control method thereof.

A trimming circuit according to an embodiment includes a first arm including a first switch connected in series between a first node and a second node and a first current source of a first current level, a second arm connected between the first node and the second node A second switch connected in series and a second current source of a second current level, the third switch being connected in parallel between the first node and the second node; 3 current level, and a third arm in parallel with the first arm and the second arm. The output current level of the second node is determined according to the on / off state of the first switch, the second switch, and the third switch, and the first current level and the third current level may be equal to each other .

The second current level may be different from the first current level and the third current level. The second current level may be higher than the first current level and the third current level.

The trimming circuit may further include an inverter connected to a control terminal of the third switch. The trimming circuit may further comprise a voltage source coupled to the first node.

A trimming circuit according to an embodiment includes a first arm including a first transistor connected in series between a first node and a second node and a first current source of a first current level, A second transistor having a second transistor connected in series and a second current source of a second current level, the second transistor being in parallel with the first arm, and a third transistor connected in series between the first node and the second node, 3 current level, and a third arm in parallel with the first arm and the second arm. The output current level of the second node is determined according to the on / off state of the first transistor, the second transistor, and the third transistor, and the first current level and the third current level may be equal to each other .

The second current level may be different from the first current level and the third current level. The second current level may be higher than the first current level and the third current level.

The polarity of the control voltage for turning on the third transistor may be opposite to the polarity of the control voltage for turning on the first transistor and the second transistor.

The trimming circuit may further comprise a voltage source coupled to the first node.

A trimming circuit control method of outputting an output current by using a plurality of combinations according to conduction states of a plurality of current sources according to an embodiment includes: determining an output current level of the output current; Finding at least two candidate combinations corresponding to the output current level among the plurality of combinations; Removing unavailable candidate combinations of the at least two candidate combinations; And selecting one of the remaining candidate combinations to control the conduction state of each of the plurality of current sources.

At least two current sources of the plurality of current sources may have the same current level. The current level of at least one current source excluding the at least two current sources among the plurality of current sources may be different from the current level of the at least two current sources. The current level of the at least one current source may be higher than the current level of the at least two current sources.

The trimming circuit and its control method according to embodiments can output the output current at a desired output current level even when the switch fails and satisfies the functional safety standard of ISO 26262. [

1A is a diagram showing a trimming circuit according to an embodiment of the present invention.
1B is a diagram showing a trimming circuit according to another embodiment of the present invention.
2 is a diagram for explaining an output current level of a trimming circuit according to embodiments of the present invention.
3 is a diagram showing a conventional trimming circuit.
4 is a diagram for explaining an output current level of an output current of a conventional trimming circuit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments may be implemented in various different forms and are not limited to the embodiments described herein.

In order to clearly illustrate the embodiments, parts not related to the description are omitted, and the same reference numerals are used for the same or similar components throughout the specification. Therefore, reference numerals of the components used in the previous drawings can be used in the following drawings.

In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and therefore, the embodiments are not necessarily limited to those shown in the drawings. In the drawings, thicknesses and regions may be exaggerated for clarity of presentation of layers and regions.

Electrical connection of two components includes not only direct connection of two components but also connection between two components via different components. Other components may include switches, resistors, capacitors, and the like. In describing the embodiments, the expression " connection " means that the connection is electrically connected when there is no expression of direct connection.

1A is a diagram showing a trimming circuit according to an embodiment of the present invention.

1A, a trimming circuit 10a includes a first arm 110a, a second arm 120a, and a third arm 130a connected in parallel to each other with reference to a first node and a second node, . Here, the first node refers to the nodes to which the first to third arms 110a, 120a, and 130a and the voltage source VDD1 are connected, and the second node refers to the node to which the output current _{I1_out} is output.

The first arm 110a includes a first switch _{SW1_1} and a first current source 111 connected in series and the second arm 120a includes a second switch _{SW1_2} and a second current source And the third arm 130a includes a third switch _{SW1_3} and a third current source 131 connected in series.

The first current source 111 has a first current level, the second current source 121 has a second current level, and the third current source 131 has a third current level. In this embodiment, at least two current sources 111 and 131 among the plurality of current sources 111, 121, and 131 have the same current level. Referring to FIG. 1A, the first current level and the third current level are equal to each other at I ₁ .

In addition, at least one current source 121 except for at least two current sources 111 and 131 having the same current level among the plurality of current sources 111, 121, and 131 may have different current levels. At this time, the current level of the current source 121 may be higher than the current level of the current sources 111 and 131. Referring to FIG. 1A, the current level of the current source 121 is 2I ₁ higher than the current level I ₁ of the current sources 111 and 131.

The first switch _{SW1_1} is controlled on and off by the first control signal S _{1_1} and the second switch SW _{1_2} is on and off controlled by the second control signal S _{1_2} , _{SW1_3} are on-off controlled by the third control signal S _{1_3} .

The inverter 190 may be connected to the control terminal of the third switch _{SW1_3} . The inverter 190 can invert the third control signal S _{1_3} .

1B is a diagram showing a trimming circuit according to another embodiment of the present invention.

Referring to FIG. 1B, the trimming circuit 10b includes a first arm 110b, a second arm 120b, and a third arm 130b connected to each other in parallel with respect to a first node and a second node . Here, the first node refers to the nodes to which the first to third arms 110b, 120b, and 130b and the voltage source VDD1 are connected, and the second node refers to the node to which the output current _{I1_out} is output.

The first arm 110b includes a first transistor _{TR1_1} and a first current source 111 connected in series and the second arm 120b includes a second transistor _{TR1_2} and a second current source 121, and a third arm 130b includes a third transistor _{TR1_3} and a third current source 131 connected in series.

The first current source 111 has a first current level, the second current source 121 has a second current level, and the third current source 131 has a third current level. In this embodiment, at least two current sources 111 and 131 among the plurality of current sources 111, 121, and 131 have the same current level. Referring to FIG. 1B, the first current level and the third current level are equal to each other at I ₁ .

In addition, at least one current source 121 except for at least two current sources 111 and 131 having the same current level among the plurality of current sources 111, 121, and 131 may have different current levels. At this time, the current level of the current source 121 may be higher than the current level of the current sources 111 and 131. Referring to FIG. 1B, the current level of the current source 121 is 2I ₁ higher than the current level I ₁ of the current sources 111 and 131.

The first transistor _{TR1_1} is controlled to be turned on and off by the first control signal S _{1_1} and the second transistor TR _{1_2} is controlled to be turned on and off by the second control signal S _{1_2} , _{1_3} TR) are controlled on and off by a third control signal (S _{1_3).}

A third polarity control voltage is in the ON state the transistor (TR _{1_3)} may be a polarity opposite to that of the control voltage which the state of the first transistor (TR _{1_1)} and the second transistor (TR _{1_2)} on. For example, the third transistor _{TR1_3} may be a PMOS transistor, and the first and second transistors _{TR1_1} and _{TR1_2} may be NMOS transistors.

2 is a diagram for explaining an output current level of a trimming circuit according to embodiments of the present invention.

Referring to FIG. 2, the graph 20 represents the value of the control signal S ₁ as the horizontal axis and the output current level of the output current I _{1_out} as the vertical axis. The control signal (S ₁₎ can be represented by 3 bits, the value of the control signal (S _{1_1)} value of a first bit, a control signal (S _{1_2)} the second bit, the control signal (S _{1_3)} the value of the .

The graph 20 of FIG. 2 may be described in accordance with the embodiment of FIG. 1A or the embodiment of FIG. 1B, but for convenience, the embodiment of FIG.

When the control signal S ₁ is "000", the first control signal S _{1_1} is off level, the second control signal S _{1_2} is off level, and the third control signal S _{1_3} is off level . However, since the third control signal _{S1_3} is inverted by the inverter 190, an on-level control signal is applied to the control terminal of the third switch _{SW1_3} . Therefore, the current level of the output current I _{1_out} corresponds to the current source 131, and therefore corresponds to I ₁ .

When the control signal S ₁ is "001", the first control signal S _{1_1} is on level, the second control signal S _{1_2} is off level, and the third control signal S _{1_3} is off level . Since the third control signal S _{1_3} is inverted by the inverter 190, an on-level control signal is applied to the control terminal of the third switch SW _{1_3} . Therefore, the current level of the output current I _{1_out} corresponds to 2 I ₁ since it depends on the current sources 111 and 131.

When the control signal S ₁ is "010", the first control signal S 1 _{_} 1 is off level, the second control signal S 1 _{_} 2 is on level, and the third control signal S 1 _{_} 3 is off level . Since the third control signal S _{1_3} is inverted by the inverter 190, an on-level control signal is applied to the control terminal of the third switch SW _{1_3} . Therefore, since the current level of the output current I _{1_out depends on} the current sources 121 and 131, it corresponds to 3I ₁ .

When the control signal S ₁ is "011", the first control signal S _{1_1} is on level, the second control signal S _{1_2} is on level, and the third control signal S _{1_3} is off level . Since the third control signal S _{1_3} is inverted by the inverter 190, an on-level control signal is applied to the control terminal of the third switch SW _{1_3} . Therefore, since the current level of the output current I _{1_out depends on} the current sources 111, 121, and 131, it corresponds to 4I ₁ .

When the control signal S ₁ is "100", the first control signal S 1 _{_} 1 is off level, the second control signal S 1 _{_} 2 is off level, and the third control signal S 1 _{_} 3 is on level . Since the third control signal _{S1_3} is inverted by the inverter 190, an off-level control signal is applied to the control terminal of the third switch _{SW1_3} . Therefore, the current level of the output current I _{1_out} corresponds to zero.

When the control signal S ₁ is "101", the first control signal S _{1_1} is on level, the second control signal S _{1_2} is off level, and the third control signal S _{1_3} is on level . Since the third control signal _{S1_3} is inverted by the inverter 190, an off-level control signal is applied to the control terminal of the third switch _{SW1_3} . Therefore, the current level of the output current I _{1_out} corresponds to the current source 111, and therefore corresponds to I ₁ .

When the control signal S ₁ is "110", the first control signal S 1 _{_} 1 is off level, the second control signal S 1 _{_} 2 is on level, and the third control signal S 1 _{_3} is on level . Since the third control signal _{S1_3} is inverted by the inverter 190, an off-level control signal is applied to the control terminal of the third switch _{SW1_3} . Therefore, the current level of the output current I _{1_out} corresponds to 2 I ₁ since it follows the current source 121.

When the control signal S ₁ is "111", the first control signal S _{1_1} is on level, the second control signal S _{1_2} is on level, and the third control signal S _{1_3} is on level . Since the third control signal _{S1_3} is inverted by the inverter 190, an off-level control signal is applied to the control terminal of the third switch _{SW1_3} . Therefore, the current level of the output current I _{1_out} is _{dependent on} the current sources 111 and 121, and thus corresponds to 3I ₁ .

A plurality of combinations according to the conduction states of the plurality of current sources 111, 121, and 131 are 2 ⁿ when n switches are used. Therefore, since there are three switches in the present embodiment, there are eight combinations. Of the eight combinations, the remaining six combinations except the two combinations of the output current levels of the output current I _{1_out} and the case of the output current levels of the output current I _{1_out} being 0 and 4I ₁ are paired in the following two combinations.

The output current level is I ₁ in the combination of the control signal S ₁ of "000" and the combination of "101", and the combination of the control signal S ₁ of "001" and the combination of "110" The output current level becomes 3I ₁ in the combination of the current level of 2 I ₁ and the combination of control signal S ₁ of "010" and "111".

Therefore, even if a failure occurs in the first switch _{SW1_1} and is short-circuited, for example, the output current _{I1_out} having the output current level I ₁ is output using the combination of the control signal S ₁ of "101" And outputs an output current _{I1_out} having an output current level of 2I ₁ by using a combination of the control signal S ₁ of "001" and outputs the output current I _{1_out} using a combination of the control signal S ₁ of "111" the current level 3I can output the _first output current (I _{1_out).}

As a result, the selectable output current level width can be narrower than conventional trimming circuits, but a trimming circuit that is more robust against switch failures can be provided.

The trimming circuit can be controlled by an external control circuit or a digital signal processor (DSP) as follows.

First, the digital signal processor can determine the output current level of the output current _{I1_out} required in the semiconductor integrated circuit in which the trimming circuit 10a is located or connected.

The digital signal processor may find at least two candidate combinations corresponding to the determined output current level of the plurality of combinations. The plurality of combinations are combinations according to the conduction states of the plurality of current sources 111, 121, and 131 as described above. At least two candidate combinations mean different combinations capable of outputting the output current ( _{I1_out} ) at the same output current level. For example, when the determined output current level is I ₁ , the combination of the control signal S ₁ of "000" and the combination of "101" may be the candidate combination.

Next, the digital signal processor may exclude unavailable candidate combinations of at least two candidate combinations. For example, when a short-circuit failure of the first switch _{SW1_1} is confirmed, the candidate combination in which the control signal S ₁ is "000" can not be used and can be excluded.

Therefore, the digital signal processor can select a combination in which the control signal S ₁ , which is one of the remaining candidate combinations, is "101 ", thereby controlling the conduction state of each of the plurality of current sources 111, 121 and 131. In the case of the example, the first switch _{SW1_1} is turned on (short-circuited) and the second and third switches _{SW1_2} and _{SW1_3} are turned off.

In the present specification, a trimming circuit having three switches is described as an embodiment, but it is possible to add switches to increase the width of the selectable output current level or to add various combinations corresponding to the same output current level.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are illustrative and explanatory only and are intended to be illustrative of the invention and are not to be construed as limiting the scope of the invention as defined by the appended claims. It is not. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10a and 10b: a trimming circuit
SW _{1_1} , SW _{1_2} , SW _{1_3} : Switch
_{TR1_1} , _{TR1_2} , _{TR1_3} : transistor
110a, 120a, 130a, 110b, 120b, 130b:
111, 121, 131: current source
190: Inverter

Claims (14)

A first arm including a first switch connected in series between a first node and a second node and a first current source of a first current level;
A second switch including a second switch connected in series between the first node and the second node and a second current source of a second current level, the second arm parallel to the first arm; And
A third switch connected in series between the first node and the second node and a third current source of a third current level, the third arm being in parallel with the first arm and the second arm,
The output current level of the second node is determined according to the ON / OFF state of the first switch, the second switch, and the third switch,
Wherein the first current level and the third current level are equal to each other,
The second current level being different from the first current level and the third current level,
Trimming circuit. delete The method according to claim 1,
Wherein the second current level is higher than the first current level and the third current level,
Trimming circuit. The method of claim 3,
Further comprising an inverter coupled to a control terminal of the third switch,
Trimming circuit. 5. The method of claim 4,
Further comprising a voltage source coupled to the first node,
Trimming circuit. A first arm comprising a first transistor connected in series between a first node and a second node and a first current source of a first current level;
A second arm comprising a second transistor connected in series between the first node and the second node and a second current source of a second current level, the second arm parallel to the first arm; And
A third transistor coupled in series between the first node and the second node and a third current source of a third current level, the third arm being in parallel with the first arm and the second arm,
The output current level of the second node is determined according to the on / off state of the first transistor, the second transistor, and the third transistor,
Wherein the first current level and the third current level are equal to each other,
The second current level being different from the first current level and the third current level,
Trimming circuit. delete The method according to claim 6,
Wherein the second current level is higher than the first current level and the third current level,
Trimming circuit. 9. The method of claim 8,
The polarity of the control voltage for turning on the third transistor is opposite to the polarity of the control voltage for turning on the first transistor and the second transistor,
Trimming circuit. 10. The method of claim 9,
Further comprising a voltage source coupled to the first node,
Trimming circuit. A trimming circuit control method for outputting an output current by using a plurality of combinations according to conduction states of a plurality of current sources,
Determining an output current level of the output current;
Finding at least two candidate combinations corresponding to the output current level among the plurality of combinations;
Removing unavailable candidate combinations of the at least two candidate combinations; And
And selecting one of the remaining candidate combinations to control the conduction state of each of the plurality of current sources
A method of controlling a trimming circuit. 12. The method of claim 11,
Wherein at least two current sources of the plurality of current sources have the same current level,
A method of controlling a trimming circuit. 13. The method of claim 12,
Wherein a current level of at least one current source excluding the at least two current sources among the plurality of current sources is different from a current level of the at least two current sources,
A method of controlling a trimming circuit. 14. The method of claim 13,
Wherein the current level of the at least one current source is higher than the current level of the at least two current sources,
A method of controlling a trimming circuit.

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