Protection circuit for power switches

Abstract

A transistor (108) is coupled between a first voltage input (102) and a voltage output (106) in a first current path (110). A first circuit element (112) is coupled between a second voltage input (104), the control terminal (108c) of the transistor, and the voltage output. A second circuit element (120) is coupled between the control terminal and ground (122) in a second current path (124) and between the control terminal and ground in a third current path (126) parallel to the second current path. The second current path includes the control terminal, the first and third terminals (120a, 120c) of the second circuit element, and ground. The third current path includes the control terminal, the second and third terminals (120b, 120c) of the second circuit element, and ground. A third circuit element (130) is coupled between the control terminal and the voltage output in a fourth current path (132). The fourth current path includes the control terminal, the first and second terminals (130a, 130b) of the third circuit element, and the voltage output.

Description

Background Art

[0001] Many modern devices include various electrical circuits. Some electrical circuits include a switch for connecting and disconnecting a power supply and a load between the power supply and the load. By connecting the power supply to the load via the switch, current can be provided from the power supply to the load to power the load. A transistor (e.g., a metal-oxide-semiconductor field-effect transistor (MOSFET)) can be used as a switch by controlling the voltage at the control terminal (e.g., the gate electrode) of the transistor.

Summary of the Invention

[0002] In one example, the circuit includes a first voltage input, a second voltage input, and a voltage output. In a first current path, a transistor is coupled between the first voltage input and the voltage output. The first current path includes the first voltage input, a first terminal of the transistor, a second terminal of the transistor, and the voltage output. In a first control path, a first circuit element is coupled between the second voltage input and the control terminal of the transistor, and in a second control path, it is coupled between the voltage output and the control terminal of the transistor. The first control path includes the second voltage input, a first terminal of the first circuit element, a third terminal of the first circuit element, and the control terminal of the transistor. The second control path includes the voltage output, a second terminal of the first circuit element, a third terminal of the first circuit element, and the control terminal of the transistor. A second circuit element is coupled between the transistor's control terminal and ground in a second current path, and between the transistor's control terminal and ground in a third current path parallel to the second current path. The second current path includes the transistor's control terminal, the first terminal of the second circuit element, the third terminal of the second circuit element, and ground. The third current path includes the transistor's control terminal, the second terminal of the second circuit element, the third terminal of the second circuit element, and ground. The third circuit element is coupled between the transistor's control terminal and a voltage output in a fourth current path. The fourth current path includes the transistor's control terminal, the first terminal of the third circuit element, the second terminal of the third circuit element, and a voltage output.

[0003] In one example, the circuit includes a first voltage input, a second voltage input, a first control signal input, a second control signal input, and a voltage output. A first transistor is coupled between the first voltage input and the voltage output in a first current path. The first current path includes a first voltage input, a first terminal of the first transistor, a second terminal of the first transistor, and a voltage output. A second transistor includes a first terminal coupled to the second voltage input, a second terminal coupled to the control terminal of the first transistor, and a control terminal coupled to the first control signal input. A third transistor includes a first terminal coupled to the control terminal of the first transistor, a second terminal coupled to the voltage output, and a control terminal coupled to the first control signal input. A fourth transistor is coupled between the control terminal of the first transistor and ground in both a second current path and a third current path parallel to the second current path. The second and third current paths include the control terminal of the first transistor, the first terminal of the fourth transistor, the second terminal of the fourth transistor, and ground. The fourth transistor includes a control terminal coupled to the second control signal input. The fifth transistor is coupled in the second current path between the control terminal of the first transistor and the first terminal of the fourth transistor. The second current path further includes the first terminal of the fifth transistor and the second terminal of the fifth transistor. The sixth transistor is coupled in the third current path between the control terminal of the first transistor and the first terminal of the fourth transistor. The third current path further includes the first terminal of the sixth transistor and the second terminal of the sixth transistor. The seventh transistor is coupled in the fourth current path between the control terminal of the first transistor and the voltage output. The fourth current path includes the control terminal of the first transistor, the first terminal of the seventh transistor, the second terminal of the seventh transistor, and a voltage output. The eighth transistor is coupled between ground and the voltage output in the fifth current path. The fifth current path includes ground, the first terminal of the eighth transistor, the second terminal of the eighth transistor, and a voltage output. The eighth transistor includes a control terminal coupled to the control terminal of the seventh transistor.The ninth transistor is coupled in the fifth current path between ground and the first terminal of the eighth transistor. The fifth current path further includes the first terminal of the ninth transistor and the second terminal of the ninth transistor.

[0004] In one example, the system includes a controller, a voltage source, a voltage converter, a load circuit element, and a switching circuit element. The controller includes a first output and a second output. The voltage converter includes an input and an output. The input of the voltage converter is coupled to the voltage source. The load circuit element includes an input. The switching circuit element is coupled to the controller, the voltage source, the voltage converter, and the load circuit element. The switching circuit element includes a first voltage input, a second voltage input, a voltage output, a first control signal input, a second control signal input, a first transistor, a transistor control circuit element, a first protection circuit element, and a second protection circuit element. The first voltage input is coupled to the voltage source. The second voltage input is coupled to the output of the voltage converter. The voltage output is coupled to the input of the load circuit element. The first control signal input is coupled to the first output of the controller. The second control signal input is coupled to the second output of the controller. The first transistor is coupled between the first voltage input and the voltage output in a first current path. The first current path includes a first voltage input, a first terminal of the first transistor, a second terminal of the first transistor, and a voltage output. The transistor control circuit element is coupled between the second voltage input and the control terminal of the first transistor in the first control path, and between the voltage output and the control terminal of the first transistor in the second control path. The transistor control circuit element includes a control terminal coupled to the first control signal input. The first control path includes a second voltage input, a first terminal of the transistor control circuit element, a third terminal of the transistor control circuit element, and the control terminal of the first transistor. The second control path includes a voltage output, a second terminal of the transistor control circuit element, a third terminal of the transistor control circuit element, and the control terminal of the first transistor. The first protection circuit element is coupled between the control terminal of the first transistor and ground in the second current path, and between the control terminal of the first transistor and ground in a third current path parallel to the second current path. The first protection circuit element includes a control terminal coupled to the second control signal input. The second current path includes the control terminal of the first transistor, the first terminal of the first protection circuit element, the third terminal of the first protection circuit element, and ground.The third current path includes the control terminal of the first transistor, the second terminal of the first protection circuit element, the third terminal of the first protection circuit element, and ground. The second protection circuit element is coupled between the control terminal of the first transistor and the voltage output in the fourth current path. The second protection circuit element includes a control terminal coupled to the voltage output. The fourth current path includes the control terminal of the first transistor, the first terminal of the second protection circuit element, the second terminal of the second protection circuit element, and the voltage output. [Brief explanation of the drawing]

[0005] [Figure 1] Here are some example circuit diagrams of switching circuits.

[0006] [Figure 2] This is an example timing diagram corresponding to the circuit in Figure 1.

[0007] [Figure 3] The following are circuit diagrams of some examples of systems including the circuit in Figure 1.

[0008] [Figure 4] Here are some other examples of switching circuits:

[0009] [Figure 5A] Here are some other examples of switching circuits: [Figure 5B] Here are some other examples of switching circuits:

[0010] [Figure 6] These are top views of some examples of integrated chips that include transistor devices.

[0011] [Figure 7] These are illustrative timing diagrams corresponding to the circuits in Figures 5A and 5B.

[0012] The same reference code or other reference designators are used to refer to the same or similar features (functionally and / or structurally). [Modes for carrying out the invention]

[0013] The following description provides numerous different examples for implementing the different features of the subject matter presented. Specific examples of components and their arrangements are described below to simplify this description. The drawings are not drawn to scale.

[0014] Figure 1 is a circuit diagram of some examples of a switching circuit 100. The circuit 100 includes a first voltage input 102, a second voltage input 104, a first control signal input 134, a second control signal input 128, and a voltage output 106. In the first current path 110, a first transistor 108 is coupled between the first voltage input 102 and the voltage output 106. The transistor 108 includes a first terminal 108a, a second terminal 108b, and a control terminal 108c. The first current path 110 includes the first voltage input 102, the first terminal 108a of the transistor 108, the second terminal 108b of the first transistor 108, and the voltage output 106. The transistor 108 is configured to selectively couple the first voltage input 102 to the voltage output 106 so that current can flow from the first voltage input 102 to the voltage output 106 via the first current path 110.

[0015] The first transistor control circuit element 112 is coupled to the control terminal 108c of the transistor 108. More specifically, the first transistor control circuit element 112 is coupled between the second voltage input 104 and the control terminal 108c of the transistor 108 in the first control path 114 (e.g., the first pull-up path). The first transistor control circuit element 112 is also coupled between the voltage output 106 and the control terminal 108c of the transistor 108 in the second control path 116 (e.g., the first pull-down path). The first transistor control circuit element 112 includes a first terminal 112a, a second terminal 112b, a third terminal 112c, and a control terminal 112d. The first control path 114 includes the second voltage input 104, the first terminal 112a of the first transistor control circuit element 112, the third terminal 112c of the first transistor control circuit element 112, and the control terminal 108c of the transistor 108. The second control path 116 includes the voltage output 106, the second terminal 112b of the first transistor control circuit element 112, the third terminal 112c of the first transistor control circuit element 112, and the control terminal 108c of the transistor 108. The control terminal 112d of the first transistor control circuit element 112 is coupled to the first control signal input 134.

[0016] The first transistor control circuit element 112 is configured to receive a first control signal (for example, the first control signal 202 in Figure 2) from a first control signal input 134 at its control terminal 112d. Based on the first control signal, the first transistor control circuit element 112 is configured to selectively couple the control terminal 108c of transistor 108 to a second voltage input 104 (via the first control path 114) or to a voltage output 106 (via the second control path 116).

[0017] For example, when the first control signal is high, the first transistor control circuit element 112 couples the second voltage input 104 to the control terminal 108c of transistor 108 via the first control path 114 (for example, the first transistor control circuit element 112 pulls up the control terminal 108c). Therefore, for example, as shown in Figure 2, the voltage at the control terminal 108c of transistor 108 is high. In response, transistor 108 turns on, and therefore the first voltage input 102 is coupled to the voltage output 106. Therefore, the voltage at the voltage output 106 is high. Conversely, when the first control signal is low, the first transistor control circuit element 112 couples the voltage output 106 to the control terminal 108c of transistor 108 via the second control path 116 (for example, the first transistor control circuit element 112 pulls down the control terminal 108c). Therefore, for example, as shown in Figure 2, the voltage at the control terminal 108c of transistor 108 is low. In response, transistor 108 turns off, and therefore the first voltage input 102 is not coupled to the voltage source 106. Therefore, the voltage at the voltage output 106 is low.

[0018] One challenge with respect to the circuit is ensuring that transistor 108 remains off when no power source is connected to circuit 100 (for example, when there is no voltage at either the first voltage input 102 or the second voltage input 104, and no signal is received at the control terminal 112d, and therefore the first transistor control circuit element 112 does not connect either the second voltage input 104 or the voltage output 106 to the control terminal 108c). In some circuits, a protective resistor (not shown) is connected between the control terminal 108c of transistor 108 and the voltage output 106 to passively connect the control terminal 108c of transistor 108 to the voltage output 106, so that transistor 108 remains off when no power source is connected to circuit 100.

[0019] However, using a protective resistor (not shown) to passively couple the control terminal 108c of transistor 108 to the voltage output 106 makes it difficult to operate in low-power mode (e.g., when transistor 108 is on and the total current consumed by the power source (not shown) is less than approximately 10 microamperes, less than approximately 8 microamperes, less than approximately 6 microamperes, or some other preferred value). For example, when transistor 108 is on, the difference between the voltage at the control terminal 108c of transistor 108 and the voltage at the voltage output 106 (e.g., the gate-source voltage Vgs) is greater than zero. Due to this non-zero voltage difference, current leaks from the control terminal 108c to the voltage output 106 through the protective resistor (not shown). This leakage current may cause the power source (not shown) to consume more current than is permissible during low-power mode. Therefore, when a protective resistor (not shown) is coupled between the control terminal 108c and the voltage output 106, low-power mode may not be obtainable.

[0020] In the various examples described herein, the circuit 100 includes a first protection circuit element 120 and a second protection circuit element 130 to ensure that the transistor 108 remains off when no power source is coupled to the circuit 100, without interfering with the low-power mode.

[0021] The first protection circuit element 120 is coupled between the control terminal 108c of the transistor 108 and the ground 122 in the second current path 124. Also, the first protection circuit element 120 is coupled between the control terminal 108c of the transistor 108 and the ground 122 in the third current path 126. The third current path 126 is parallel to the second current path 124. The first protection circuit element 120 includes a first terminal 120a, a second terminal 120b, a third terminal 120c, and a control terminal 120d. The second current path 124 includes the control terminal 108c of the transistor 108, the first terminal 120a of the first protection circuit element 120, the third terminal 120c of the first protection circuit element 120, and the ground 122. The third current path 126 includes the control terminal 108c of the transistor 108, the second terminal 120b of the first protection circuit element 120, the third terminal 120c of the first protection circuit element 120, and the ground 122. The control terminal 120d of the first protection circuit element 120 is coupled to the second control signal input 128.

[0022] The second protection circuit element 130 is coupled between the control terminal 108c of the transistor 108 and the voltage output 106 in the fourth current path 132. The second protection circuit element 130 includes a first terminal 130a, a second terminal 130b, and a control terminal 130c. The fourth current path 132 includes the control terminal 108c of the transistor 108, the first terminal 130a of the second protection circuit element 130, the second terminal 130b of the second protection circuit element 130, and the voltage output 106. The control terminal 130c of the second protection circuit element 130 is coupled to the voltage output 106.

[0023] The first protection circuit element 120 is configured to receive a second control signal (e.g., the second control signal 204 in FIG. 2) from the second control signal input 128 at the control terminal 120d. The first protection circuit element 120 is configured to selectively couple the control terminal 108c of the transistor 108 to ground 122 (via the second current path 124 and the third current path 126) based on the second control signal and the voltage at the control terminal 108c of the transistor 108. The second protection circuit element 130 is configured to selectively couple the control terminal 108c of the transistor 108 to the voltage output 106 (via the fourth current path 132) based on the voltage at the voltage output 106.

[0024] For example, when the second control signal (at the control terminal 120d of the first protection circuit element 120) is high and the voltage at the control terminal 108c of the transistor 108 is not negative (e.g., when a power supply source is not coupled to the circuit 100), for example, as shown in FIG. 2, the first protection circuit element 120 is on and the second protection circuit element 130 is off. Therefore, the control terminal 108c of the transistor 108 is coupled to ground 122 (via the second current path 124 and the third current path 126), but not to the voltage output 106, and thus the voltage at the control terminal 108c of the transistor 108 is low. In response, the transistor 108 is off. Therefore, when a power supply source is not coupled to the circuit 100, the first protection circuit element 120 can ensure that the transistor 108 remains off.

[0025] When the voltage at voltage output 106 (and at the control terminal 130c of the second protection circuit element 130) is negative (for example, during circuit testing such as a direct power injection (DPI) test), the first protection circuit element 120 is off and the second protection circuit element 130 is on. Therefore, the control terminal 108c of the transistor is coupled to voltage output 106 but not to ground 122, and thus the difference between the voltage at the control terminal 108c of transistor 108 and the voltage at voltage output 106 is approximately zero. In response to this, transistor 108 is off. Therefore, the second protection circuit element 130 ensures that transistor 108 remains off when the voltage at voltage output 106 is negative.

[0026] When the second control signal is low (for example, when transistor 108 is on in normal power mode or low power mode) and the voltage at voltage output 106 is not negative, for example, as shown in Figure 2, the first protection circuit element 120 is off and the second protection circuit element 130 is off. In response, the control terminal 108c of transistor 108 is not coupled to ground 122 by the first protection circuit element 120 and is not coupled to voltage output 106 by the second protection circuit element 130. Therefore, current leakage from the control terminal 108c to ground 122 or voltage output 106 can be eliminated, and thus the power supply current consumption requirements for low power mode (e.g., less than approximately 10 microamperes, less than approximately 8 microamperes, less than approximately 6 microamperes, or some other suitable value) can be achieved. In some examples, low power mode can be enabled when the load at voltage output 106 is low in order to improve the efficiency of the circuit.

[0027] Figure 2 is an illustrative timing diagram corresponding to circuit 100 in Figure 1.

[0028] Referring to Figures 1 and 2, during the normal on-mode (for example, when a power source (not shown) is coupled to circuit 100, transistor 108 is on, and there is no power supply current limit), the first control signal 202 is high. In response, the first transistor control circuit element 112 couples the second voltage input 104 to the control terminal 108c via the first control path 114 (for example, pulling up the control terminal 108c to the second voltage input 104). Therefore, the voltage at the control terminal 108c of transistor 108 is high. In response, transistor 108 is on, and the first voltage input 102 is coupled to the voltage source 106. Therefore, the voltage at the voltage output 106 is high. Also, the second control signal 204 is low. Therefore, the first protection circuit element 120 is off. Also, since the voltage at the voltage output 106 is not negative, the second protection circuit element 130 is off.

[0029] During the normal off mode (for example, when a power source (not shown) is coupled to circuit 100, transistor 108 is off, and there is no power supply current limit), the first control signal 202 is low. In response, the first transistor control circuit element 112 couples the voltage output 106 to the control terminal 108c via the second control path 116 (for example, pulling down the control terminal 108c to the voltage output 106). Therefore, the voltage at the control terminal 108c of transistor 108 is low. In response, transistor 108 is off, and the first voltage input 102 is not coupled to the voltage output 106. Therefore, the voltage at the voltage output 106 is low. Also, the second control signal 204 is high. Since the second control signal 204 is high and the voltage at the control terminal 108c of transistor 108 is not negative, the first protection circuit element 120 is on. Furthermore, since the voltage at voltage output 106 is not negative, the second protection circuit element 130 is off.

[0030] During the low-power mode (for example, when a power source (not shown) is coupled to circuit 100, transistor 108 is turned on, and the amount of current consumed by the power source must be less than approximately 10 microamperes, less than approximately 8 microamperes, less than approximately 6 microamperes, or some other suitable value), the first control signal 202 is high. In response, the first transistor control circuit element 112 couples the second voltage input 104 to the control terminal 108c via the first control path 114 (for example, pulling up the control terminal 108c to the second voltage input 104). Therefore, the voltage at the control terminal 108c of transistor 108 is high. In response, transistor 108 is on, and therefore the first voltage input 102 is coupled to the voltage output 106. Therefore, the voltage at the voltage output 106 is high. Also, the second control signal 204 is low. Therefore, the first protection circuit element 120 is off. Furthermore, since the voltage output is not negative, the second protection circuit element 130 is off.

[0031] In some cases, a negative voltage may be applied to the voltage output 106 (for example, during circuit testing such as a direct power injection (DPI) test or other circuit tests). During this negative output voltage mode (for example, when the voltage at the voltage output 106 is negative, a power source is coupled to circuit 100, and transistor 108 is off), transistor 108 may be temporarily turned on. Because the voltage at the voltage output 106 is negative, the second protection circuit element 130 is turned on. In response, the control terminal 108c of the transistor is coupled to the voltage output 106 via the fourth current path 132. Therefore, the difference between the voltage at the control terminal 108c of transistor 108 and the voltage at the voltage output (for example, the gate-source voltage Vgs) drops to approximately zero. In response, transistor 108 is turned off.

[0032] During sleep mode (for example, when a power source is coupled to circuit 100, transistor 108 is off, and the amount of current consumed by the power source connected to the circuit must be less than 2 microamperes, less than 1 microampere, or some other suitable value), the first control signal 202 is disabled, and therefore the transistor control circuit element 112 does not couple the control terminal 108c to either the second voltage input 104 or the voltage output 106. The second control signal 204 remains enabled and is high. Since the second control signal 204 is high and the voltage at the control terminal 108c of transistor 108 is not negative, the first protection circuit element 120 is on. In response, the control terminal 108c of transistor 108 is coupled to ground 122 via the second current path 124 and the third current path 126. Therefore, the voltage at the control terminal 108c of transistor 108 is low. In response, the first transistor 108 is off, and therefore the first voltage input 102 is not coupled to the voltage output 106. Thus, the voltage at voltage output 106 is low. Also, since the voltage at voltage output 106 is not negative, the second protection circuit element 130 is off.

[0033] During the power-off mode (for example, when the power source is not coupled to circuit 100 and transistor 108 is off), the first control signal 202 is inactive, and therefore the transistor control circuit element 112 does not couple the control terminal 108c to either the second voltage input 104 or the voltage output 106. The second control signal 204 remains active and is high. Since the second control signal 204 is high and the voltage at the control terminal 108c of transistor 108 is not negative, the first protection circuit element 120 is on. In response, the control terminal 108c of transistor 108 is coupled to ground 122 via the second current path 124 and the third current path 126. Therefore, the voltage at the control terminal 108c of transistor 108 is low. In response, the first transistor 108 is off, and therefore the first voltage input 102 is not coupled to the voltage output 106. Therefore, the voltage at the voltage output 106 is low. Furthermore, since the voltage at voltage output 106 is not negative, the second protection circuit element 130 is off.

[0034] In some cases, the second control signal 204 is generated using a power-on reset (POR) signal that is valid regardless of the operating mode, and therefore the second control signal 204 is ineffective in sleep mode and power-off mode.

[0035] Figure 3 is a schematic diagram of several examples of a system 300 that includes the circuit 100 of Figure 1. The system 300 further includes a controller 302, a voltage source 304, a voltage converter 306, and a load circuit element 308.

[0036] The controller 302 (for example, a microcontroller or some other suitable controller circuit element) includes a first output 302a and a second output 302b. The first output 302a of the controller 302 is coupled to the first control signal input 134 of the circuit 100. The second output 302b of the controller 302 is coupled to the second control signal input 128 of the circuit 100.

[0037] The voltage source 304 (e.g., a battery or some other suitable direct current (DC) voltage source) includes a first terminal 304a (e.g., a positive terminal) and a second terminal 304b (e.g., a negative terminal). The first terminal 304a is coupled to the first voltage input 102 of the circuit 100 and the voltage converter 306. In some examples, the second terminal 304b is coupled to ground 122.

[0038] The voltage converter 306 (e.g., a charge pump, a boost DC-DC converter, or some other suitable voltage conversion circuit element) includes an input 306a and an output 306b. The input 306a of the voltage converter 306 is coupled to the first terminal 304a of the voltage source 304. The output 306b of the voltage converter 306 is coupled to the second voltage input 104 of the circuit 100. In some examples, the voltage source 304 and the voltage converter 306 are part of a voltage supply.

[0039] The load circuit element 308 includes a first terminal 308a and a second terminal 308b. The first terminal 308a of the load circuit element 308 is coupled to the voltage output 106 of the circuit 100. In some examples, the second terminal 308b of the load circuit element 308 is coupled to ground 122. The load circuit element 308 may include, for example, a resistor, an inductor, and a capacitor.

[0040] The controller 302 is configured to generate a first control signal (e.g., the first control signal 202 in Figure 2) and a second control signal (e.g., the second control signal 204 in Figure 2). The controller 302 is configured to provide the first control signal to the control terminal 112d of the first transistor control circuit element 112 via the first control signal input 134 in order to control the first transistor control circuit element 112. The controller 302 is configured to provide the second control signal to the control terminal 120d of the first protection circuit element 120 via the second control signal input 128 in order to control the first protection circuit element 120.

[0041] The voltage source 304 is configured to generate a first voltage (e.g., a DC voltage) at the first terminal 304a. The voltage converter 306 is configured to receive the first voltage from the voltage source 304 (at input 306a) and generate a second voltage (at output 306b) that is greater than the first voltage. In some examples, the first voltage is in the range of approximately 3 volts to approximately 40 volts, or some other preferred range. The second voltage is approximately 8 volts higher than the first voltage, 10 volts higher than the first voltage, 12 volts higher than the first voltage, or some other preferred voltage.

[0042] The circuit 100 is configured to supply current to the load circuit element 308 by selectively coupling the voltage source 304 to the load circuit element 308 using the transistor 108.

[0043] Figure 4 is a schematic diagram of several examples of circuits 400 similar to circuit 100 in Figure 1, in which the first transistor control circuit element 112, the first protection circuit element 120, and the second protection circuit element 130 include multiple transistors.

[0044] For example, the first transistor control circuit element 112 includes a second transistor 402 (e.g., a pull-up transistor) and a third transistor 404 (e.g., a pull-down transistor). Transistor 402 is coupled in the first control path 114 between a second voltage input 104 and a control terminal 108c of transistor 108. The first control path includes the second voltage input 104, the first terminal 402a of transistor 402, the second terminal 402b of transistor 402, and the control terminal 108c of transistor 108.

[0045] Transistor 404 is coupled in the second control path 116 between the voltage output 106 and the control terminal 108c of transistor 108. The second control path 116 includes the voltage output 106, the first terminal 404a of transistor 404, the second terminal 404b of transistor 404, and the control terminal 108c of transistor 108.

[0046] In some examples, the first transistor control circuit element 112 further includes an inverter 426. The input (unsigned) of the inverter 426 is coupled to the first control signal input 134. The control terminal 402c of transistor 402 is coupled to the output (unsigned) of inverter 426. Also, the control terminal 404c of transistor 404 is coupled to the output (unsigned) of inverter 426.

[0047] Inverter 426 is configured to receive a first control signal (for example, the first control signal 202 in Figure 7) from a first control signal input 134. Inverter 426 inverts the first control signal and outputs the inverted first control signal. Transistors 402 and 404 are configured to receive the inverted first control signal from inverter 426 at control terminals 402c and 404c, respectively. Transistor 402 is configured to selectively couple the control terminal 108c of transistor 108 to the second voltage input 104 (via the first control path 114) based on the (inverted) first control signal. Transistor 404 is configured to selectively couple the control terminal 108c of transistor 108 to the voltage output 106 (via the second control path 116) based on the (inverted) first control signal.

[0048] For example, when the first control signal is high (when the inverted first control signal is low), for example as shown in Figure 7, transistor 402 is on and transistor 404 is off. In response, the second voltage input 104 is coupled to the control terminal 108c of transistor 108 via the first control path 114. Therefore, the voltage at the control terminal 108c of transistor 108 is high. In response, transistor 108 is turned on, and therefore the first voltage input 102 is coupled to the voltage output 106. Therefore, the voltage at the voltage output 106 is high. Conversely, when the first control signal is low (when the inverted first control signal is high), for example as shown in Figure 7, transistor 402 is off and transistor 404 is on. In response, the voltage output 106 is coupled to the control terminal 108c of transistor 108 via the second control path 116. Therefore, the voltage at the control terminal 108c is low. In response, transistor 108 turns off, and as a result, the first voltage input 102 is not coupled to voltage source 106. Therefore, the voltage at voltage output 106 is low.

[0049] The first protection circuit element 120 includes a fourth transistor 406, a fifth transistor 408, a sixth transistor 410, and a first resistor 412. Transistor 406 is coupled between the control terminal 108c of the first transistor 108 and ground 122 in both the second current path 124 and the third current path 126. The control terminal 406c of transistor 406 is coupled to the second control signal input 128.

[0050] In the second current path 124, transistor 408 is coupled between the control terminal 108c of transistor 108 and the first terminal 406a of transistor 406. The control terminal 408c of transistor 408 is coupled to the first terminal 408a of transistor 408 so that transistor 408 becomes a "diode-connected" transistor, allowing a unidirectional current flow from the control terminal 108c of transistor 108 to ground 122.

[0051] Transistor 410 is coupled in the third current path 126 between the control terminal 108c of transistor 108 and the first terminal 406a of transistor 406. Resistor 412 is coupled in the third current path 126 between the control terminal 108c of transistor 108 and the first terminal 410a of transistor 410. The control terminal 410c of transistor 410 is coupled (via resistor 412) to the first terminal 408a of transistor 410 so that transistor 410 becomes a “diode-connected” transistor that allows a unidirectional flow of current from the control terminal 108c of transistor 108 to ground 122.

[0052] The second current path 124 includes the control terminal 108c of transistor 108, the first terminal 408a of transistor 408, the second terminal 408b of transistor 408, the first terminal 406a of transistor 406, the second terminal 406b of transistor 406, and ground 122. The third current path 126 includes the control terminal 108c of transistor 108, the first terminal 412a of resistor 412, the second terminal 412b of resistor 412, the first terminal 410a of transistor 410, the second terminal 410b of transistor 410, the first terminal 406a of transistor 406, the second terminal 406b of transistor 406, and ground 122.

[0053] Transistor 406 is configured to receive a second control signal (for example, the second control signal 204 in Figure 7) from the second control signal input 128 at its control terminal 406c. Transistors 406, 408, and 410 are configured to selectively couple the control terminal 108c of transistor 108 to ground 122 (via the second current path 124 and the third current path 126) based on the second control signal and the voltage at the control terminal 108c of transistor 108.

[0054] For example, when the second control signal (e.g., the second control signal 204 in Figure 7) is high, transistor 406 is on, for example, as shown in Figure 7. When transistor 406 is on and the voltage at the control terminal 108c is not negative, transistors 408 and 410 are on (e.g., transistors 408 and 410 are forward biased). When transistor 408 is on, the control terminal 108c of transistor 108 is coupled to ground 122 via the second current path 124. However, the voltage drop across transistor 408 is greater than zero. Therefore, the voltage at the control terminal 108c of transistor 108 is greater than zero. To bring the voltage at the control terminal 108c of transistor 108 closer to zero, transistor 410 is included in the first protection circuit element 120. Transistor 410 has a reduced voltage drop. For example, transistor 410 is a "natural" device with a voltage drop of approximately zero. When transistor 410 is on, the control terminal 108c of transistor 108 is coupled to ground 122 via the third current path 126, and therefore the voltage at the control terminal 108c of transistor 108 is pulled down to almost zero. Resistor 412 is included in the third current path 126 to limit the current in the third current path 126 in order to protect transistor 410. Therefore, transistor 410 allows a small amount of current to flow from the control terminal 108c of transistor 108 to ground 122 (via the second current path 124), while transistor 408 allows the majority of the current to flow from the control terminal 108c of transistor 108 to ground 122 (via the second current path 124). When the control terminal 108c of transistor 108 is coupled to ground 122, the voltage at the control terminal 108c of transistor 108 is low. In response to this, transistor 108 is off, and therefore the first voltage input 102 is not coupled to the voltage output. Therefore, the voltage at voltage output 106 is low.

[0055] When the second control signal is low, for example, as shown in Figure 7, transistor 406 is off, and therefore transistors 408 and 410 are also off. Therefore, the control terminal 108c of transistor 108 is not connected to ground 122.

[0056] Furthermore, when the voltage at voltage output 106 is negative, transistors 408 and 410 are off (for example, reverse-biased), as shown in Figure 7. Therefore, the control terminal 108c of transistor 108 is not coupled to ground 122.

[0057] The second protection circuit element 130 includes a seventh transistor 414, an eighth transistor 416, a second resistor 418, and a ninth transistor 420. Transistor 414 is coupled between the control terminal 108c of transistor 108 and the voltage output 106 in the fourth current path 132. The fourth current path includes the control terminal 108c of transistor 108, the first terminal 414a of transistor 414, the second terminal 414b of transistor 414, and the voltage output 106.

[0058] Transistor 416 is coupled between the voltage output 106 and ground 122 in the fifth current path 424. The control terminal 416c of transistor 416 is coupled to the first terminal 416a of transistor 416 so that transistor 416 becomes a “diode-connected” transistor that allows a unidirectional flow of current from ground 122 to the voltage output 106. The control terminal 414c of transistor 414 is coupled to the control terminal 416c of transistor 416.

[0059] Resistor 418 is coupled between the first terminal 416a of transistor 416 and ground 122 in the fifth current path 424. Transistor 420 is coupled between the second terminal 418b of resistor 418 and ground 122 in the fifth current path 424. The control terminal 420c of transistor 420 is coupled to the second terminal 420b of transistor 420 so that transistor 420 becomes a “diode-connected” transistor that allows a unidirectional current flow from ground 122 to the voltage output 106. In some examples, transistor 420 forms a body diode 422 coupled between the second terminal 420b and the first terminal 420a of transistor 420.

[0060] The fifth current path 424 includes ground 122, the second terminal 420b of transistor 420, the first terminal 420a of transistor 420, the second terminal 418b of resistor 418, the first terminal 418a of resistor 418, the first terminal 416a of transistor 416, the second terminal 416b of transistor 416, and the voltage output 106.

[0061] Transistor 414 is configured to selectively couple the control terminal 108c of transistor 108 to the voltage output 106 (via the fourth current path 132) based on the voltage at the voltage output 106. For example, when the voltage at the voltage output 106 is negative, transistors 416 and 420 are on (for example, transistors 416 and 420 are forward biased). Therefore, current can flow from ground 122 to the voltage output 106 via the fifth current path 424. In response to transistors 416 and 420 being turned on, transistor 414 is turned on. Since transistor 414 is on, the control terminal 108c of transistor 108 is coupled to the voltage output 106. Therefore, the voltage at the control terminal 108c of transistor 108 is approximately equal to the voltage at the voltage output 106. In response, transistor 108 is off, and therefore the first voltage input 102 is not coupled to the voltage output 106.

[0062] Furthermore, when the voltage at voltage output 106 is not negative, for example, as shown in Figure 7, transistors 416 and 420 are off (e.g., reverse-biased), and therefore transistor 414 is off. Consequently, the control terminal 108c is not coupled to voltage output 106.

[0063] During the low-power mode, the second control signal is low, and the voltage at voltage output 106 is not negative. In response, transistors 406, 408, 410, 416, 420, and 414 are off, and therefore the control terminal 108c is not coupled to ground 122 or voltage output 106. Thus, current leakage from control terminal 108c to ground 122 or voltage output 106 can be eliminated. As a result, the power supply current consumption requirement for the low-power mode can be met.

[0064] Transistors 408, 410, 416, and 420 are referred to as “diode-connected transistors,” but in some examples, these transistors may be referred to as unidirectional current devices and / or as diodes, etc.

[0065] Figures 5A and 5B are schematic diagrams of several examples of a circuit 500 similar to the circuit 400 in Figure 4, in which a tenth transistor 506 is coupled between a first voltage input 102 and a voltage output 106 in a sixth current path 507 parallel to the first current path 110.

[0066] The circuit 500 includes a first part 501a and a second part 501b. The first part 501a includes a first voltage input 102, a second voltage input 104, a first control signal input 134, a second control signal input 128, a voltage output 106, a transistor 108, a first transistor control circuit element 112 (including transistors 402, 404, and inverter 426), a first protection circuit element 120 (including transistors 406, 408, 410, and resistor 412), and a second protection circuit element 130 (including transistors 414, 416, resistor 418, and transistor 420), which are coupled together as shown with reference to Figure 4. Furthermore, the first portion 501a includes a first current path 110, a first control path 114, a second control path 116, a second current path 124, a third current path 126, a fourth current path 132, and a fifth current path 424, as shown with reference to Figure 4.

[0067] In short, the second part 501b is a copy of the first part 501a. More specifically, the second part 501b includes a first voltage input 102, a third voltage input 502, a third control signal input 505, a second control signal input 128, a voltage output 106, a tenth transistor 506, a second transistor control circuit element 504, a third protection circuit element 510, and a fourth protection circuit element 512.

[0068] Transistor 506 is coupled between the first voltage input 102 and the voltage output 106 in a sixth current path 507. The sixth current path 507 includes the first voltage input 102, the first terminal 506a of transistor 506, the second terminal 506b of transistor 506, and the voltage output 106. The sixth current path 507 is parallel to the first current path 110.

[0069] The second transistor control circuit element 504 includes an eleventh transistor 514 and a twelfth transistor 518. Transistor 514 is coupled between a third voltage input 502 and the control terminal 506c of transistor 506 in a third control path 516 (e.g., a second pull-up path). The third control path 516 includes the third voltage input 502, the first terminal 514a of transistor 514, the second terminal 514b of transistor 514, and the control terminal 506c of transistor 506. Transistor 518 is coupled between a voltage output 106 and the control terminal 506c of transistor 506 in a fourth control path 520 (e.g., a second pull-down path). The fourth control path 520 includes the voltage output 106, the second terminal 518b of transistor 518, the first terminal 518a of transistor 518, and the control terminal 506c of transistor 506.

[0070] In some examples, the second transistor control circuit element 504 further includes an inverter 548. The input (unsigned) of the inverter 548 is coupled to the third control signal input 505. The control terminal 514c of transistor 514 is coupled to the output (unsigned) of inverter 548. The control terminal 518c of transistor 518 is coupled to the output (unsigned) of inverter 548.

[0071] The third protection circuit element 510 includes a 13th transistor 522, a 14th transistor 528, a 15th transistor 530, and a third resistor 532. Transistors 528 and 522 are coupled in a seventh current path 524 between the control terminal 506c of transistor 506 and ground 122. The seventh current path 524 includes the control terminal 506c of transistor 506, the first terminal 528a of transistor 528, the second terminal 528b of transistor 528, the first terminal 522a of transistor 522, the second terminal 522b of transistor 522, and ground 122.

[0072] The resistor 532, transistor 530, and transistor 522 are coupled in an eighth current path 526 between the control terminal 506c of transistor 506 and ground 122. The eighth current path 526 includes the control terminal 506c of transistor 506, the first terminal 532a of resistor 532, the second terminal 532b of resistor 532, the first terminal 530a of transistor 530, the second terminal 530b of transistor 530, the first terminal 522a of transistor 522, the second terminal 522b of transistor 522, and ground 122.

[0073] The control terminal 522c of transistor 522 is coupled to the second control signal input 128. The control terminal 528c of transistor 528 is coupled to the first terminal 528a of transistor 528 so that transistor 528 becomes a "diode-connected" transistor that allows a unidirectional flow of current from the control terminal 108c of transistor 108 to ground 122 (via the seventh current path 524). The control terminal 530c of transistor 530 is coupled to the first terminal 530a of transistor 530 (via resistor 532) so that transistor 530 becomes a "diode-connected" transistor that allows a unidirectional flow of current from the control terminal 108c of transistor 108 to ground 122 (via the eighth current path 526).

[0074] The 14th protection circuit element 512 includes a 16th transistor 534, a 17th transistor 538, a 4th resistor 542, and an 18th transistor 544. Transistor 534 is coupled between the control terminal 506c of transistor 506 and the voltage output 106 in a 9th current path 536. The 9th current path 536 includes the control terminal 506c of transistor 506, the first terminal 534a of transistor 534, the second terminal 534b of transistor 534, and the voltage output 106.

[0075] Transistor 538, resistor 542, and transistor 544 are coupled between the voltage output 106 and ground 122 in a tenth current path 540. The tenth current path 540 includes ground 122, the second terminal 544b of transistor 544, the first terminal 544a of transistor 544, the second terminal 542b of resistor 542, the first terminal 542a of resistor 542, the first terminal 538a of transistor 538, the second terminal 538b of transistor 538, and the voltage output 106. In some examples, transistor 544 forms a body diode 546 coupled between the second terminal 544b and the first terminal 544a of transistor 544.

[0076] The control terminal 534c of transistor 534 is coupled to the control terminal 538c of transistor 538. The control terminal 538c of transistor 538 is coupled to the first terminal 538a of transistor 538 so that transistor 538 becomes a "diode-connected" transistor that allows a unidirectional flow of current from ground 122 to the voltage output 106 (through the tenth current path 540). The control terminal 544c of transistor 544 is coupled to the second terminal 544b of transistor 544 so that transistor 544 becomes a "diode-connected" transistor that allows a unidirectional flow of current from ground 122 to the voltage output 106 (through the tenth current path 540).

[0077] In some illustrative systems, a first voltage input 102 is coupled to a voltage source (e.g., voltage source 304 in Figure 3), a second voltage input 104 is coupled to the output of a first voltage converter (e.g., output 306b of voltage converter 306 in Figure 3), and a third voltage input 502 is coupled to the output of a second voltage converter (not shown) different from the first voltage converter. A third control signal input 505 is coupled to the output of a controller (e.g., the output of controller 302 in Figure 3 (not shown)).

[0078] In some examples, transistors 108, 404, 406, 408, 410, 414, 416, 420, 506, 518, 522, 528, 530, 534, 538, and 544 are n-channel metal oxide semiconductor field-effect transistors (MOSFETs), and transistors 402 and 514 are p-channel MOSFETs. Although the transistors shown in Figures 4, 5A, and 5B are illustrated and described as MOSFETs, in some other examples the transistors may be alternatively the corresponding bipolar junction transistors (BJTs), junction field-effect transistors (JFETs), or several other suitable transistors.

[0079] Transistor 108 contains a first number of channels, and transistor 506 contains a second number of channels greater than the first number of channels. For example, transistor 108 contains one channel, and transistor 506 contains two or more channels (e.g., two channels, three channels, four channels, five channels, etc.). Other numbers of channels are also possible.

[0080] Figure 6 is a top view of an example of an integrated chip including transistors 108 and 506. Transistor 108 includes a channel 602 extending between a first source / drain region 604a and a second source / drain region 604b. A first gate electrode 606 extends over the channel 602. The first source / drain region 604a is coupled to a first voltage input 102, forming the first terminal 108a of transistor 108. The second source / drain region 604b is coupled to a voltage output 106, forming the second terminal 108b of transistor 108. The first gate electrode 606 forms the control terminal 108c of transistor 108.

[0081] Furthermore, transistor 506 includes a first channel 608a extending between the first source / drain region 604a and the third source / drain region 604c, a second channel 608b extending between the third source / drain region 604c and the fourth source / drain region 604d, a third channel 608c extending between the fourth source / drain region 604d and the fifth source / drain region 604e, and a fourth channel 608d extending between the fifth source / drain region 604e and the sixth source / drain region 604f. The first finger of the second gate electrode 610 extends over the first channel 608a, the second finger of the second gate electrode 610 extends over the second channel 608b, the third finger of the second gate electrode 610 extends over the third channel 608c, and the fourth finger of the second gate electrode 610 extends over the fourth channel 608d. The first source / drain region 604a, the fourth source / drain region 604d, and the sixth source / drain region 604f are coupled to the first voltage input 102 to form the first terminal 506a of transistor 506. The third source / drain region 604c and the fifth source / drain region 604e are coupled to the voltage output 106 to form the second terminal 506b of transistor 506. The second gate electrode 610 forms the control terminal 506c of transistor 506.

[0082] Although transistors 108 and 506 are illustrated as planar transistors in Figure 6, in some other examples, transistors 108 and 506 may be replaced by three-dimensional transistors (e.g., fin field-effect transistors, gate-all-around field-effect transistors, etc.).

[0083] Figure 7 is an illustrative timing diagram corresponding to circuit 500 in Figures 5A and 5B.

[0084] During normal ON mode (for example, when the power supply (voltage source 304 and voltage converter 306) is coupled to circuit 500, and the first voltage input 102 is coupled to voltage output 106 via both the first current path 110 and the sixth current path 507, and there is no power supply current limit), the first control signal 202 is high (when the inverted first control signal is low), and the third control signal 702 is high (when the inverted third control signal is low). In response, transistors 404 and 518 are off, while transistors 402 and 514 are on, so that the second voltage input 104 is coupled to control terminal 108c (via the first control path 114), and the third voltage input 502 is coupled to control terminal 506c (via the third control path 516). Therefore, the voltage at control terminal 108c is high, and the voltage at control terminal 506c is high. In response, transistors 108 and 506 are turned on, and therefore the first voltage input 102 is coupled to the voltage output 106 through transistor 108 (through the first current path 110) and through transistor 506 (through the sixth current path 507). Therefore, the voltage at voltage output 106 is high. Also, the second control signal 204 is low. Therefore, transistors 406 and 522 are off, and therefore transistors 408, 410, 528, and 530 are off. Also, since the voltage output is not negative, transistors 416, 420, 538, and 544 are off, and therefore transistors 414 and 534 are off.

[0085] During the normal off mode (for example, when the power source is coupled to circuit 500, the first voltage input 102 is not coupled to voltage output 106, and there is no power supply current limit), the first control signal 202 is low and the third control signal 702 is low. In response, transistors 402 and 514 are off, while transistors 404 and 518 are on, so that voltage output 106 is coupled to the control terminal 108c of transistor 108 (via the second control path 116) and to the control terminal 506c of transistor 506 (via the fourth control path 520). Therefore, the voltage at control terminal 108c is low and the voltage at control terminal 506c is low. In response, transistor 108 is off and transistor 506 is off, so that the first voltage input 102 is not coupled to voltage output 106. Therefore, voltage output 106 is low. Also, the second control signal 204 is high. Since the second control signal 204 is high, transistors 406, 408, and 410 are on, and transistors 522, 528, and 530 are on. Also, since the voltage at control terminal 108c is not negative and the voltage at control terminal 506c is not negative, transistors 416, 420, 538, and 544 are off, and therefore transistors 414 and 534 are off.

[0086] During the low-power mode (for example, when the power source is coupled to circuit 500, transistor 108 is on, transistor 506 is off, and the amount of current consumed by the power source must be less than approximately 10 microamperes, less than approximately 8 microamperes, less than approximately 6 microamperes, or some other suitable value), the first control signal 202 is high and the third control signal 702 is low. In response, transistor 402 is on, transistor 514 is off, transistor 404 is off, and transistor 518 is on, so the second voltage input 104 is coupled to control terminal 108c and the voltage output 106 is coupled to control terminal 506c. Thus, the voltage at control terminal 108c is high and the voltage at control terminal 506c is low. In response, transistor 108 is ON and transistor 506 is OFF, so the first voltage input 102 is coupled to the voltage output 106 through transistor 108 (through the first current path) but not through transistor 506. Because the first voltage input 102 is coupled to the voltage output 106 through transistor 108 (through the first current path) but not through transistor 506, the voltage at voltage output 106 may be slightly lower than in the normal ON mode, but the voltage at voltage output 106 is still high. Also, the second control signal 204 is low. Therefore, transistors 406 and 522 are OFF, and therefore transistors 408, 410, 528, and 530 are OFF. Also, because the voltage at voltage output 106 is not negative, transistors 416, 420, 538, and 544 are OFF, and therefore transistors 414 and 534 are OFF.

[0087] In some examples, a second voltage input 104 is coupled to a first voltage converter (e.g., voltage converter 306 in Figure 3), and a third voltage input 502 is coupled to a second voltage converter (not shown). The first voltage converter (not shown) is smaller (e.g., has fewer stages) and more efficient than the second voltage converter. During low-power mode, the second voltage input 104 is coupled to control terminal 108c, but the third voltage input 502 is not coupled to control terminal 506c, so that when a more efficient voltage converter (first voltage converter) is used, the less efficient voltage converter (second voltage converter) is disconnected from the circuit. By using a more efficient voltage converter and disconnecting the less efficient voltage converter during low-power mode, the current consumed by the power source (e.g., voltage source 304 in Figure 3, first voltage converter 306 in Figure 3, and second voltage converter (not shown)) during low-power mode is reduced. As a result, the power supply current consumption requirements for low-power mode can be met.

[0088] Furthermore, since transistor 108 is used in both the normal on-mode and the low-power mode, the resistance between the first voltage input 102 and the voltage output 106 can be only slightly higher than during the normal on-mode. Therefore, the difference between the voltage at voltage output 106 during the normal on-mode and the voltage at voltage output 106 during the low-power mode can be very small. Also, since transistor 108 is used in both the normal on-mode and the low-power mode, the transition from the low-power mode to the normal on-mode can occur more quickly.

[0089] During the negative output voltage mode (for example, when the voltage at voltage output 106 is negative, the power source is coupled to circuit 500, and the first voltage input 102 is not coupled to voltage output 106), transistors 108 and 506 may be temporarily turned on. Because the voltage at voltage output 106 is negative, transistors 420, 416, 544, and 538 are on, and therefore transistors 414 and 534 are also on. In response, control terminal 108c is coupled to voltage output 106 through transistor 414 (via the fourth current path 132), and control terminal 506c is coupled to voltage output 106 through transistor 534 (via the current path 536). Thus, the difference between the voltage at control terminal 108c and the voltage at voltage output 106 drops to approximately zero, and the difference between the voltage at control terminal 506c and the voltage at voltage output 106 drops to approximately zero. In response, transistor 108 turns off, and transistor 506 turns off.

[0090] During sleep mode (for example, when a power source is coupled to circuit 500, the first voltage input 102 is not coupled to voltage output 106, and the amount of current consumed by the power source connected to the circuit must be less than approximately 2 microamperes, less than 1 microampere, or some other suitable value), the first control signal 202 and the third control signal 702 are disabled. Therefore, transistors 402 and 404 do not couple their control terminal 108c to either the second voltage input 104 or the voltage output 106, and transistors 514 and 518 do not couple their control terminal 506c to either the third voltage input 502 or the voltage output 106. However, the second control signal 204 remains enabled and is high. Since the second control signal 204 is high, and the voltage at control terminal 108c is not negative, and the voltage at control terminal 506c is not negative, transistors 406, 408, 410, 522, 528, and 530 are on. Therefore, control terminal 108c is coupled to ground 122 (via the second current path 124 and the third current path 126), and control terminal 506c is coupled to ground 122 (via the seventh current path 524 and the eighth current path 526). In response, transistors 108 and 506 are off. Therefore, the voltage at voltage output 106 is low. Also, since the voltage at voltage output 106 is not negative, transistors 416, 420, 538, and 544 are off, and thus transistors 414 and 534 are off.

[0091] During the power-off mode (for example, when the power source is not coupled to circuit 500 and the first voltage input 102 is not coupled to voltage output 106), the first control signal 202 and the third control signal 702 are disabled. Therefore, transistors 402 and 404 do not couple their control terminal 108c to either the second voltage input 104 or the voltage output 106, and transistors 514 and 518 do not couple their control terminal 506c to either the third voltage input 502 or the voltage output 106. However, the second control signal 204 remains enabled and is high. Since the second control signal 204 is high, and the voltage at control terminal 108c is not negative, and the voltage at control terminal 506c is not negative, transistors 406, 408, 410, 522, 528, and 530 are on. Therefore, control terminal 108c is connected to ground 122 (via the second current path 124 and the third current path 126), and control terminal 506c is connected to ground 122 (via the seventh current path 524 and the eighth current path 526). In response, transistors 108 and 506 are off. Therefore, the voltage at voltage output 106 is low. Also, since the voltage at voltage output 106 is not negative, transistors 416, 420, 538, and 544 are off, and thus transistors 414 and 534 are off.

[0092] Since protection circuit elements 120, 130, 510, and 512 only require the operation of a second control signal 204 (which is effective even when the power source is not connected to circuit 500), protection circuit elements 120, 130, 510, and 512 can reliably protect transistors 108 and 506 even when the power source is not connected to circuit 500.

[0093] Although the above methods are illustrated and described as a series of actions or events, the illustrated order of such actions or events is not limited. For example, some actions or events may occur in a different order, and / or may occur simultaneously with other actions or events not illustrated and / or described herein. Furthermore, some illustrated actions or events are optional for implementing one or more aspects or examples of the herein. Also, one or more of the actions or events shown herein may be carried out in one or more separate actions and / or stages. In some examples, the above methods may be implemented on a computer-readable medium using instructions stored in memory.

[0094] In this description, the term “to connect” may encompass any connection, communication, or signaling path that enables a functional relationship consistent with this description. For example, if device A generates a signal to control device B in order to perform a certain action, then (a) in the first example, device A is connected to device B by a direct connection, or (b) in the second example, if the intervening component C does not alter the functional relationship between device A and device B, device A is connected to device B via the intervening component C, and device B is controlled by device A via the control signal generated by device A.

[0095] A device "configured" to perform a certain task or function may be configured (e.g., programmed and / or wired) at the time of manufacture by the manufacturer to perform that function, and / or may be configured (or reconfigurable) after manufacture by the user to perform that function and / or other additional or alternative functions. Such configuration may be via firmware and / or software programming of the device, via the construction of hardware components and interconnections of the device, and / or via layout, or a combination thereof.

[0096] As used herein, the terms “terminal,” “node,” “interconnection,” “pin,” and “lead” are interchangeable. Unless otherwise specified, these terms are generally used to mean the interconnections or terminations between device elements, circuit elements, integrated circuits, devices, or other electronic or semiconductor components.

[0097] In this specification, a circuit or device described as including certain components may instead be adapted to be coupled with those components to form the described circuit element or device. For example, a structure described as including one or more semiconductor elements (such as transistors), one or more passive elements (such as resistors, capacitors, and / or inductors), and / or one or more sources (voltage sources and / or current sources) may instead include only semiconductor elements (e.g., semiconductor dies and / or integrated circuit (IC) packages) in a single physical device, and may be adapted to be coupled with at least some of the passive elements and / or sources to form the described structure during or after manufacturing, for example, by an end user and / or a third party.

[0098] While the use of specific transistors is described herein, other transistors (or equivalent devices) may be used instead with little or no modification to the remaining circuit elements. For example, metal oxide silicon FETs ("MOSFETs") (n-channel MOSFETs, nMOSFETs, or p-channel MOSFETs, pMOSFETs), bipolar transistors (BJTs, e.g., NPN or PNP), insulated-gate bipolar transistors (IGBTs), and / or junction field-effect transistors (JFETs) may be used instead of, or in conjunction with, the devices described herein. The transistors may be depletion-mode devices, drain-extension devices, enhancement-mode devices, natural transistors, or transistors of other device structures. The devices may also be mounted on or on silicon substrates (Si), silicon carbide substrates (SiC), gallium nitride substrates (GaN), or gallium arsenide substrates (GaAs).

[0099] In the examples described, certain elements are included in a certain integrated circuit, while other elements are outside the integrated circuit, but in other examples, more or fewer features may be incorporated into the integrated circuit. Also, some or all of the features illustrated as being outside the integrated circuit may be included inside the integrated circuit, and / or some features illustrated as being inside the integrated circuit may be incorporated outside the integrated circuit. As used herein, the term “integrated circuit” means one or more circuits that are (1) incorporated in / on a semiconductor substrate, (2) incorporated in a single semiconductor package, (3) incorporated in the same module, and / or (4) incorporated in / on the same printed circuit board.

[0100] The use of the term "grounding" in the foregoing description includes chassis grounding, earth grounding, floating grounding, virtual grounding, digital grounding, common grounding, and / or any other form of grounding connection applicable to or suitable for the teachings herein. Unless otherwise stated, "approximately," "nearly," or "substantially" preceding a value means ±10 percent of the stated value, and if the value is zero, it means a reasonable range near zero.

[0101] Modifications to the embodiments described within the claims are possible, and other implementations are also possible.

Claims

1. It is a circuit, A first voltage input, a second voltage input, and a voltage output, A transistor coupled between the first voltage input and the voltage output in a first current path, wherein the first current path includes the first input, the first terminal of the transistor, the second terminal of the transistor, and the voltage output, A first circuit element coupled between the second voltage input and the control terminal of the transistor in a first control path, and coupled between the voltage output and the control terminal of the transistor in a second control path, wherein the first control circuit includes the second voltage input, the first terminal of the first circuit element, the third terminal of the first circuit element, and the control terminal of the transistor, and the second control path includes the voltage output, the second terminal of the first circuit element, the third terminal of the first circuit element, and the control terminal of the transistor, A second circuit element coupled between the control terminal of the transistor and ground in a second current path, and coupled between the control terminal of the transistor and ground in a third current path parallel to the second current path, wherein the second current path includes the control terminal of the transistor, a first terminal of the second circuit element, a third terminal of the second circuit element, and ground, and the third current path includes the control terminal of the transistor, a second terminal of the second circuit element, a third terminal of the second circuit element, and ground, In the fourth current path, a third circuit element coupled between the control terminal of the transistor and the voltage output, wherein the fourth current path includes the control terminal of the transistor, the first terminal of the third circuit element, the second terminal of the third circuit element, and the voltage output, A circuit that includes this.

2. The circuit according to claim 1, wherein the third circuit element includes a control terminal coupled to the voltage output, and the circuit further comprises A first control signal input is coupled to the control terminal of the first circuit element, A second control signal input is coupled to the control terminal of the second circuit element, A circuit that includes this.

3. The circuit according to claim 1, wherein the transistor is a first transistor, and the second circuit element is In both the second current path and the third current path, a second transistor is coupled between the control terminal of the first transistor and ground, wherein the second current path and the third current path further include the first terminal of the second transistor and the second terminal of the second transistor, In the second current path, a first unidirectional current device is coupled between the control terminal of the first transistor and the first terminal of the second transistor, wherein the second current path further includes the first terminal of the first unidirectional current device and the second terminal of the first unidirectional current device, In the third current path, a second unidirectional current device is coupled between the control terminal of the first transistor and the first terminal of the second transistor, wherein the third current path further includes the first terminal of the second unidirectional current device and the second terminal of the second unidirectional current device, A circuit that includes this.

4. The circuit according to claim 3, wherein the third circuit element is In the fourth current path, a third transistor is coupled between the control terminal and the voltage output of the first transistor, wherein the fourth current path further includes the first terminal and the second terminal of the third transistor, In a fifth current path, a third unidirectional current device is coupled between the voltage output and ground, wherein the fifth current path includes the voltage output, a first terminal of the third unidirectional current device, a second terminal of the third unidirectional current device, and ground, In the fifth current path, a fourth unidirectional current device is coupled between the second terminal of the third unidirectional current device and ground, wherein the fifth current path further includes a first terminal of the fourth unidirectional current device and a second terminal of the fourth unidirectional current device, and the control terminal of the third transistor is coupled to the second terminal of the third unidirectional current device and the first terminal of the fourth unidirectional current device, A circuit that includes this.

5. The circuit according to claim 4, further comprising a first control signal input coupled to the control terminal of the second transistor.

6. The circuit according to claim 1, wherein the transistor is a first transistor, and the circuit further comprises A third voltage input and A second transistor coupled between the first voltage input and the voltage output in a fifth current path parallel to the first current path, wherein the fifth current path includes the first voltage input, the first terminal of the second transistor, the second terminal of the second transistor, and the voltage output, A fourth circuit element coupled between the third voltage input and the control terminal of the second transistor in a third control path, and coupled between the voltage output and the control terminal of the second transistor in a fourth control path, wherein the third control circuit includes the third voltage input, the first terminal of the fourth circuit element, the third terminal of the fourth circuit element, and the control terminal of the second transistor, and the fourth control path includes the voltage output, the second terminal of the fourth circuit element, the third terminal of the fourth circuit element, and the control terminal of the second transistor, A fifth circuit element coupled between the control terminal of the second transistor and ground in a sixth current path, and coupled between the control terminal of the second transistor and ground in a seventh current path parallel to the sixth current path, wherein the sixth current path includes the control terminal of the second transistor, the first terminal of the fifth circuit element, the third terminal of the fifth circuit element, and ground, and the seventh current path includes the control terminal of the second transistor, the second terminal of the fifth circuit element, the third terminal of the fifth circuit element, and ground, In the eighth current path, a sixth circuit element coupled between the control terminal of the second transistor and the voltage output, wherein the eighth current path includes the control terminal of the second transistor, the first terminal of the sixth circuit element, the second terminal of the sixth circuit element, and the voltage output, A circuit that includes this.

7. The circuit according to claim 1, wherein the first control path is a pull-up path, the second control path is a pull-down path, and the first circuit element is a transistor control circuit element including a pull-up transistor in the pull-up path and a pull-down transistor in the pull-down path.

8. It is a circuit, A first voltage input, a second voltage input, a first control signal input, a second control signal input, and a voltage output, A first transistor coupled between the first voltage input and the voltage output in a first current path, wherein the first current path includes the first voltage input, the first terminal of the first transistor, the second terminal of the first transistor, and the voltage output, A second transistor comprising a first terminal coupled to the second voltage input, a second terminal coupled to the control terminal of the first transistor, and a control terminal coupled to the first control signal input, A third transistor including a first terminal connected to the control terminal of the first transistor, a second terminal connected to the voltage output, and a control terminal connected to the input of the first control signal, A fourth transistor coupled between the control terminal of the first transistor and ground in both a second current path and a third current path parallel to the second current path, wherein the second current path and the third current path include the control terminal of the first transistor, a first terminal of the fourth transistor, a second terminal of the fourth transistor, and ground, and the fourth transistor includes a control terminal coupled to the second control signal input. In the second current path, a fifth transistor is coupled between the control terminal of the first transistor and the first terminal of the fourth transistor, wherein the second current path further includes the first terminal of the fifth transistor and the second terminal of the fifth transistor, In the third current path, a sixth transistor is coupled between the control terminal of the first transistor and the first terminal of the fourth transistor, wherein the third current path further includes the first terminal of the sixth transistor and the second terminal of the sixth transistor, In the fourth current path, a seventh transistor is coupled between the control terminal and the voltage output of the first transistor, wherein the fourth current path includes the control terminal of the first transistor, the first terminal of the seventh transistor, the second terminal of the seventh transistor, and the voltage output of the seventh transistor, In the fifth current path, an eighth transistor is coupled between ground and the voltage output, wherein the fifth current path includes ground, a first terminal of the eighth transistor, a second terminal of the eighth transistor, and the voltage output, and the eighth transistor includes a control terminal coupled to the control terminal of the seventh transistor. In the fifth current path, a ninth transistor is coupled between ground and the first terminal of the eighth transistor, wherein the fifth current path further includes the first terminal of the ninth transistor and the second terminal of the ninth transistor, A circuit that includes this.

9. The circuit according to claim 8, wherein the fifth transistor and the sixth transistor are diode-connected transistors adapted to allow a unidirectional current flow from the control terminal of the first transistor to the ground, and the eighth transistor and the ninth transistor are diode-connected transistors adapted to allow a unidirectional current flow from the ground to the voltage output.

10. The circuit according to claim 8, wherein the control terminal of the fifth transistor is coupled to the first terminal of the fifth transistor, the control terminal of the sixth transistor is coupled to the first terminal of the sixth transistor, the control terminal of the eighth transistor is coupled to the first terminal of the eighth transistor, and the control terminal of the ninth transistor is coupled to the second terminal of the ninth transistor.

11. The circuit according to claim 8, further, In the third current path, a first resistor is coupled between the control terminal of the first transistor and the first terminal of the sixth transistor, In the fifth current path, a second resistor is coupled between the first terminal of the eighth transistor and the first terminal of the ninth transistor, A circuit that includes this.

12. The circuit according to claim 8, further, A third voltage input and In a sixth current path parallel to the first current path, a tenth transistor is coupled between the first voltage input and the voltage output, Includes, A circuit in which the sixth current path includes the first voltage input, the first terminal of the tenth transistor, the second terminal of the tenth transistor, and the voltage output.

13. The circuit according to claim 12, further, An eleventh transistor is coupled between the control terminal of the tenth transistor and ground in both a seventh current path and an eighth current path parallel to the seventh current path, wherein the seventh current path and the eighth current path include the control terminal of the tenth transistor, the first terminal of the eleventh transistor, the second terminal of the eleventh transistor, and ground, In the seventh current path, a twelfth transistor is coupled between the control terminal of the tenth transistor and the first terminal of the eleventh transistor, wherein the seventh current path further includes the first terminal of the twelfth transistor and the second terminal of the twelfth transistor, In the eighth current path, a thirteenth transistor is coupled between the control terminal of the tenth transistor and the first terminal of the eleventh transistor, wherein the eighth current path further includes the first terminal of the thirteenth transistor and the second terminal of the thirteenth transistor, In the ninth current path, a 14th transistor is coupled between the control terminal and the voltage output of the 10th transistor, wherein the ninth current path includes the control terminal of the 10th transistor, the first terminal of the 14th transistor, the second terminal of the 14th transistor, and the voltage output of the 14th transistor, In the tenth current path, a fifteenth transistor is coupled between ground and the voltage output, wherein the tenth current path includes ground, a first terminal of the fifteenth transistor, a second terminal of the fifteenth transistor, and the voltage output, and the fifteenth transistor includes a control terminal coupled to the control terminal of the fourteenth transistor, In the tenth current path, a sixteenth transistor is coupled between the first terminal of the fifteenth transistor and ground, wherein the tenth current path further includes the first terminal of the sixteenth transistor and the second terminal of the sixteenth transistor, A circuit that includes this.

14. The circuit according to claim 13, further, A third control signal input, A 17th transistor including a first terminal coupled to the second voltage input, a second terminal coupled to the control terminal of the 10th transistor, and a control terminal coupled to the third control signal input, An 18th transistor, which includes a first terminal connected to the control terminal of the 10th transistor, a second terminal connected to the voltage output, and a control terminal connected to the third control signal input, A circuit that includes this.

15. The circuit according to claim 13, wherein the first transistor includes a first number of channels, and the tenth transistor has a second number of channels, the second number being greater than the first number.

16. It is a system, A controller including a first output and a second output, Voltage source and A voltage converter including an input and an output, wherein the input of the voltage converter is coupled to the voltage source, A load circuit element including an input, A switching circuit coupled to the controller, the voltage source, the voltage converter, and the load circuit element, Includes, The aforementioned switching circuit A first voltage input coupled to the voltage source, A second voltage input coupled to the output of the voltage converter, The voltage output coupled to the input of the load circuit element, A first control signal input coupled to the first output of the controller, A second control signal input coupled to the second output of the controller, A first transistor coupled between the first voltage input and the voltage output in a first current path, wherein the first current path includes the first voltage input, the first terminal of the first transistor, the second terminal of the first transistor, and the voltage output, A transistor control circuit element, coupled in a first control path between the second voltage input and the control terminal of the first transistor, and coupled in a second control path between the voltage output and the control terminal of the first transistor, wherein the transistor control circuit element includes a control terminal coupled to the first control signal input, the first control path includes the second voltage input, the first terminal of the transistor control circuit element, the third terminal of the transistor control circuit element, and the control terminal of the first transistor, and the second control path includes the voltage output, the second terminal of the transistor control circuit element, the third terminal of the transistor control circuit element, and the control terminal of the first transistor, A first protection circuit element coupled between the control terminal of the first transistor and ground in a second current path, and coupled between the control terminal of the first transistor and ground in a third current path parallel to the second current path, wherein the first protection circuit element includes a control terminal coupled to the second control signal input, the second current path includes the control terminal of the first transistor, the first terminal of the first protection circuit element, the third terminal of the first protection circuit element, and ground, and the third current path includes the control terminal of the transistor, the second terminal of the first protection circuit element, the third terminal of the first protection circuit element, and ground, In the fourth current path, a second protection circuit element is coupled between the control terminal of the first transistor and the voltage output, wherein the second protection circuit element includes a control terminal coupled to the voltage output, and the fourth current path includes the control terminal of the first transistor, the first terminal of the second protection circuit element, the second terminal of the second protection circuit element, and the voltage output, A system that includes this.

17. The system according to claim 16, wherein the first protective circuit element is In both the second current path and the third current path, a second transistor is coupled between the control terminal of the first transistor and ground, wherein the second current path and the third current path further include a first terminal of the second transistor and a second terminal of the second transistor, and the second transistor includes a control terminal coupled to the second control signal input. In the second current path, a first unidirectional current device is coupled between the control terminal of the first transistor and the first terminal of the second transistor, wherein the second current path further includes the first terminal of the first unidirectional current device and the second terminal of the first unidirectional current device, In the third current path, a second unidirectional current device is coupled between the control terminal of the first transistor and the first terminal of the second transistor, wherein the third current path further includes the first terminal of the second unidirectional current device and the second terminal of the second unidirectional current device, A system that includes this.

18. The system according to claim 17, wherein the second protection circuit element is In the fourth current path, a third transistor is coupled between the control terminal and the voltage output of the first transistor, wherein the fourth current path further includes the first terminal and the second terminal of the third transistor, In a fifth current path, a third unidirectional current device is coupled between the ground and the voltage output, wherein the fifth current path includes the ground, a first terminal of the third unidirectional current device, a second terminal of the third unidirectional current device, and the voltage output, In the fifth current path, a fourth unidirectional current device is coupled between ground and the first terminal of the third unidirectional current device, wherein the fifth current path further includes a first terminal of the fourth unidirectional current device and a second terminal of the fourth unidirectional current device, and the control terminal of the third transistor is coupled to the first terminal of the third unidirectional current device and the first terminal of the fourth unidirectional current device, A system that includes this.

19. The circuit according to claim 16, further, A second transistor coupled between the first voltage input and the voltage output in a fifth current path parallel to the first current path, wherein the fifth current path includes the first voltage input, the first terminal of the second transistor, the second terminal of the second transistor, and the voltage output, A third protection circuit element is coupled between the control terminal of the second transistor and ground in a sixth current path, and between the control terminal of the second transistor and ground in a seventh current path parallel to the sixth current path, wherein the third protection circuit element includes a control terminal coupled to the second control signal input, the sixth current path includes the control terminal of the second transistor, the first terminal of the third protection circuit element, the third terminal of the third protection circuit element, and ground, and the seventh current path includes the control terminal of the second transistor, the second terminal of the third protection circuit element, the third terminal of the third protection circuit element, and ground, In the eighth current path, a fourth protection circuit element is coupled between the control terminal of the second transistor and the voltage output, wherein the fourth protection circuit element includes a control terminal coupled to the voltage output, and the eighth current path includes the control terminal of the second transistor, the first terminal of the fourth protection circuit element, the second terminal of the fourth protection circuit element, and the voltage output, A system that includes this.

20. A system according to claim 16, wherein the voltage source is a battery, the voltage converter is a charge pump, and the controller is a microcontroller.

Images