JP5743463B2 - Power control device - Google Patents

Description

The present invention relates to a power supply control device having a plurality of power supply ICs, and more particularly to a power supply control device in which each of the plurality of power supply ICs generates a power supply voltage having a voltage value set in the power supply IC and outputs the power supply voltage to a load.

  2. Description of the Related Art In recent years, with the increase in speed, functionality, and cost of inkjet printers and the like, SOC (System On Chip) has been adopted for internal electronic circuits.

  The SOC is an ASIC (Application Specific Integrated Circuit), a CPU (Central Processing Unit), a memory, a logic circuit, a USB (Universal Serial Bus) interface, or other IP (Intial Protial AD, etc.). It is a chip that has been made.

  There are an increasing number of cases where the SOC is manufactured by a semiconductor fine process. As a result, the number of power sources for supplying power to the SOC is increasing. For example, a 3.3V power supply is required for I / O (Input / Output), and a 1.2V power supply is required for driving the internal logic circuit.

  When using a plurality of power supplies, it is necessary to mount a plurality of power supply ICs (Integrated Circuits) on the system board in order to generate a plurality of voltages. The power supply IC is, for example, a DC / DC converter IC or a three-terminal regulator.

  Further, when using a plurality of power supplies, the sequence (order and time) for starting or stopping the output of the voltage generated by each of the plurality of power supplies needs to be determined in advance. This is to prevent deterioration or destruction of the SOC (semiconductor). Specifically, for example, the voltage for driving the internal logic circuit is output, and then the voltage for I / O is output within 100 milliseconds.

  A technique for controlling a sequence when each of a plurality of power supplies is disconnected is disclosed in, for example, Patent Document 1.

  In the technique disclosed in Patent Document 1, when an abnormality occurs in any of a plurality of power supplies, a state in which a predetermined disconnection sequence is reversed is suppressed to a minimum time.

  Here, when an abnormality occurs in any one of a plurality of power sources, it is necessary to stop the operations of all the plurality of power sources and maintain the stopped state. This is because when an abnormality occurs in the power supply, a large current may flow and the current may decrease, and it is not desirable to continue that state.

  A technique for realizing such an operation is disclosed in Patent Document 2, for example.

  In the technique disclosed in Patent Document 2, a circuit is provided that is associated with each of a plurality of power supplies and detects a voltage abnormality of each of the plurality of power supplies. When a voltage abnormality is detected in any of the plurality of power supplies, this is notified to the other power supplies. Each of the plurality of power supplies includes a terminal for receiving notification of voltage abnormality of another power supply. When the notification of voltage abnormality is received at the terminal, the operation is stopped and the stopped state is maintained.

Japanese Patent Laid-Open No. 5-204496 JP 2001-5539 A

  Here, a general-purpose power supply IC generally does not have a terminal for receiving a notification that an abnormality has occurred in the power supply system of another power supply IC. This is because space is saved by reducing the number of pins so that it can be easily adopted in as many applications as possible. Alternatively, a general-purpose power supply IC is not supposed to be used in combination with other power supply ICs.

  If the technique disclosed in Patent Document 2 described above is used, each of the plurality of power supply ICs can receive notification that an abnormality has occurred in the power supply system of another power supply IC.

  However, when the technique disclosed in Patent Document 2 is used, it is necessary to add a circuit or the like around the power supply IC, and there is a problem that the configuration becomes complicated.

In order to solve the above problem, a power supply control device according to the present invention provides a second power supply other than the first power supply circuit while the first power supply circuit outputs a power supply voltage having a predetermined voltage value to the SOC. A power supply control device for generating a power supply voltage of a predetermined voltage value in a circuit ,
Switch signal control means for changing the switch signal to switch the switch to an on state;
Whether the difference between the voltage value of the power supply voltage output from the first power supply circuit and the predetermined voltage value is greater than or equal to a predetermined value by detecting a signal based on the power supply voltage output from the first power supply circuit Determination means for determining;
Generation of power supply voltage by the first power supply circuit when the determination means determines that the difference between the voltage value of the power supply voltage output from the first power supply circuit and a predetermined voltage value is greater than or equal to a predetermined value First stopping means for stopping
If generation of the supply voltage to the first power supply circuit is stopped, it has a second stop means for stopping the generation of the supply voltage by the second power supply circuit,
By switching the switch to the ON state by the switch signal, the determination unit determines that the difference between the detected voltage value and the predetermined voltage value is greater than or equal to a predetermined value. Stopping generation of power supply voltage by the first power supply circuit;
The SOC is operated by detecting a signal indicating a reset release state after a lapse of a predetermined time required for the first and second power supply circuits to output a power supply voltage having a predetermined voltage value,
The switch signal control means switches a switch when a signal indicating the reset release state after the lapse of the predetermined time is detected and the voltage value output from the second power supply circuit is determined to be equal to or less than a threshold value. A switch signal is changed in order to switch to an on state .

  Since the present invention is configured as described above, when an abnormality occurs in one of the power supply systems of the plurality of power supply ICs, the operation of all the plurality of power supply ICs is stopped without complicating the configuration. Can be made.

It is a block diagram which shows the structure of one Embodiment of the electric power supply system to which the power supply control apparatus by this invention is applied. 3 is a timing chart for explaining an operation when power is supplied to the power supply system shown in FIG. 1. 4 is a timing chart for explaining an operation when an abnormality occurs in the power supply voltage output from the first power supply IC after the output of the power supply voltage is started in the power supply system shown in FIG. 1. 6 is a timing chart for explaining an operation when an abnormality occurs in the power supply voltage output from the second power supply IC after the output of the power supply voltage is started in the power supply system shown in FIG. 1. It is a block diagram for demonstrating the structure of the other form of the electric power supply system to which the power supply control apparatus by this invention is applied .

  Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a block diagram illustrating one embodiment of a configuration of an electric power supply system using a power control apparatus according to the present invention.

  As shown in FIG. 1, the power supply system of the present embodiment includes a power supply system 10 and an SOC 20 that is a load.

  The power supply system 10 includes a power supply IC 100 that is a first power supply IC and a power supply IC 120 that is a second power supply IC. The power supply system 10 includes a switch 111 and a gate 112 that are divided voltage adjustment units, a voltage monitoring unit 113, and a resistor 114 and a second resistor that constitute a divided voltage generation unit. A resistor 115, a coil 116, and a capacitor 117 are provided. Note that the gate 112 operates as a control unit that controls the switch 111.

  The power supply IC 100 is, for example, a DC / DC converter IC, and includes an internal power supply unit 101, a DC / DC converter unit 102, a power-on reset unit 107, an oscillation unit 108, a timer unit 109, and a reset-out terminal 110. I have.

  The internal power supply unit 101 receives a voltage output from the outside, and generates a voltage having a voltage value of about 3.3 V to 5 V necessary for the operation of each unit of the power supply IC 100 from the received voltage. In the present embodiment, the voltage value of the voltage output from the outside and received by the internal power supply unit 101 and a DC / DC converter unit 102 described later is 24V.

  The power-on reset unit 107 detects the voltage value of the voltage output from the outside. Then, when the detected voltage value reaches a predetermined voltage value, the power-on reset unit 107 outputs an operation start signal for starting the operation of the DC / DC converter unit 102 and the timer unit 109 to the DC / DC converter unit 102 and Output to the timer unit 109.

  The DC / DC converter unit 102 receives a voltage output from the outside. When the DC / DC converter unit 102 receives the operation start signal output from the power-on reset unit 107, the DC / DC converter unit 102 generates a power supply voltage having a voltage value set in the power supply IC 100 by switching the received voltage. In the present embodiment, the voltage value set in the power supply IC 100 is 1.2V. The DC / DC converter unit 102 includes a switching unit 103, a stop / hold unit 104, an abnormality detection unit 105, and a voltage detection unit 106.

  The switching unit 103 switches the received voltage at a frequency of about 100 KHz to 1 MHz. The switching unit 103 stores energy in the coil 116 when the switching unit 103 is on. The switching unit 103 moves the energy stored in the coil 116 to the capacitor 117 when the switching unit 103 is in the off state. By repeating this, the received voltage value is converted into a voltage value set in the power supply IC 100. That is, the potential difference between the electrodes of the capacitor 117 becomes the voltage value of the power supply voltage output from the power supply IC 100. The power supply voltage output from the power supply IC 100 is input to the SOC 20 via the output line 11 and is divided by the resistors 114 and 115 to generate a divided voltage a. The generated divided voltage a is input to the voltage detection unit 106 and the abnormality detection unit 105, and the voltage value of the divided voltage a is detected by the voltage detection unit 106 and the abnormality detection unit 105. The switching unit 103 stops switching while receiving a first stop instruction signal output from the stop holding unit 104 and stopping the switching unit 103. That is, generation of the power supply voltage is stopped while the switching unit 103 receives the first stop instruction signal.

  The voltage detection unit 106 includes a reference voltage source (not shown) having a predetermined reference voltage value, and the switching unit 103 is set so that the detected voltage value of the divided voltage a is substantially the same as the predetermined reference voltage value. Control. As a result, the voltage value of the power supply voltage output from the power supply IC 100 is stabilized at 1.2V.

  Similar to the voltage detection unit 106, the abnormality detection unit 105 includes a reference voltage source (not shown) having a predetermined reference voltage value. The abnormality detection unit 105 compares the detected voltage value of the divided voltage a with a predetermined reference voltage value. When the difference between the detected voltage value of the divided voltage a and a predetermined reference voltage value is equal to or greater than a predetermined value, the abnormality detection unit 105 determines that some abnormality has occurred, and detects abnormality indicating that fact. A signal is output to the stop holding unit 104. When the voltage detection unit 106 controls the voltage value of the divided voltage a to be substantially the same as the predetermined reference voltage value, when the difference is equal to or larger than the predetermined value, an overcurrent flows through the SOC 20. It is assumed that some abnormality has occurred. Therefore, the abnormality detection unit 105 regards a state where the difference between the detected voltage value of the divided voltage a and a predetermined reference voltage value is equal to or greater than a predetermined value as an abnormality.

  Upon receiving the abnormality detection signal output from the abnormality detection unit 105, the stop holding unit 104 starts outputting the first stop instruction signal to the switching unit 103. At the same time, the stop holding unit 104 outputs a second stop instruction signal for stopping the output of the reset-out signal from the reset-out terminal 110 to the timer unit 109. The reset-out signal will be described later.

  The timer unit 109 includes a timer (not shown) that counts a predetermined time. The predetermined time is, for example, the time from when each of the power supply ICs 100 and 120 starts generating the power supply voltage and stably outputs the power supply voltage at the voltage value set for each. The timer unit 109 resets a reset state signal indicating that the power supply IC 100 is not in an operating state until the operation start signal output from the power-on reset unit 107 is received after the power supply system 10 is turned on. 110 is output. When the timer unit 109 receives the operation start signal output from the power-on reset unit 107, the timer unit 109 starts the timer. Then, the timer unit 109 starts outputting a reset release state signal indicating that the power supply IC 100 is in an operating state to the reset-out terminal 110 after the predetermined time has elapsed since the timer was started. Note that while the reset-out terminal 110 receives the reset release state signal, the reset-out signal is output from the reset-out terminal 110 to the SOC 20 via the signal line 13. Further, when the timer unit 109 receives the second stop instruction signal output from the stop holding unit 104, the timer unit 109 stops outputting the reset release state signal and outputs the reset state signal to the reset-out terminal 110.

  The oscillation unit 108 constitutes an oscillation circuit together with a vibrator connected to the outside of the power supply IC 100 and supplies a clock signal necessary for each unit of the power supply IC 100 to operate. The clock supplied from the oscillation unit 108 is, for example, a clock that is a basis of a switching cycle when the DC / DC converter unit 102 performs switching, a clock of the timer unit 109, or the like.

  The resistor 114 is connected to the output line 11. The resistor 115 is connected in series with the resistor 114 and is connected to the ground. Note that the voltage value at the connection point between the resistor 114 and the resistor 115 is the voltage value of the divided voltage a described above.

  The gate 112 is connected to the output line 12 for outputting the power supply voltage of the power supply IC 120 to the SOC 20 and the signal line 13. When a reset-out signal is flowing through the signal line 13, the gate 112 decreases when the voltage value of the power supply voltage output from the power supply IC 120 falls below a predetermined value according to the voltage value set in the power supply IC 120. , Signal c is output.

  One end of the switch 111 receives a voltage output from the outside, and the other end is connected to a connection point between the resistor 114 and the resistor 115. When the switch 111 receives the signal c output from the gate 112, the switch 111 switches from the off state to the on state. When the switch 111 is turned on, an external current flows into the connection point between the resistor 114 and the resistor 115. At this time, the divided voltage a is affected by the flowing current, and the voltage value changes. In the present embodiment, the voltage value of the voltage output from the outside and received by one end of the switch 111 is 24V. For this reason, when the switch 111 is turned on, the voltage value of the divided voltage a increases.

  The voltage monitoring unit 113 is, for example, a comparator. The voltage monitoring unit 113 is connected to the output line 11 and detects the voltage value of the power supply voltage output from the power supply IC 100. The voltage monitoring unit 113 outputs the signal b to the power supply IC 120 while the detected voltage value is larger than a value determined in advance according to the voltage value set in the power supply IC100. Note that the output line 11 and the power supply IC 120 may be directly connected without using the voltage monitoring unit 113 as long as the specification allows the power supply IC 120 to operate when a voltage of 1.2 V is input to the power supply IC 120.

  The power supply IC 120 is, for example, a three-terminal regulator. The power supply IC 120 includes an enable terminal 121 and receives the signal b output from the voltage monitoring unit 113 at the enable terminal 121. The power supply IC 120 receives a voltage output from the outside. Then, while receiving the signal b at the enable terminal 121, the power supply IC 120 generates a power supply voltage having a voltage value set in the power supply IC 120 from the received voltage. In this embodiment, the voltage value set in the power supply IC 120 is 3.3V. Then, the power supply IC 120 outputs the generated power supply voltage to the SOC 20 via the output line 12. When the output line 11 and the power supply IC 120 are directly connected without using the voltage monitoring unit 113, the output line 11 and the enable terminal 121 are connected. The power supply IC 120 generates the power supply voltage while the voltage value of the voltage received at the enable terminal 121 is larger than a value determined in advance according to the voltage value set in the power supply IC100.

  The SOC 20 includes a power supply terminal 201 that receives a power supply voltage output from the power supply IC 100 and a power supply terminal 202 that receives a power supply voltage output from the power supply IC 120. The SOC 20 includes a reset terminal 203 that receives a reset-out signal output from the reset-out terminal 110 of the power supply IC 100. The SOC 20 operates while receiving a reset-out signal at the reset terminal 203.

  Below, operation | movement of the power supply system 10 comprised as mentioned above is demonstrated.

  First, an operation when power is turned on to the power supply system 10 shown in FIG. 1 will be described.

  FIG. 2 is a timing chart for explaining the operation when the power supply system 10 shown in FIG. 1 is turned on. In FIG. 2, the power supply voltage output from the power supply IC 100 is expressed as “1.2 V output”, and the power supply voltage output from the power supply IC 120 is expressed as “3.3 V output”. . The same applies to FIGS. 3 and 4 referred to in the following description.

When the power supply system shown in FIG. 1 is turned on, the timer unit 109 outputs a reset state signal to the reset-out terminal 110. At this time, the power supply IC 100 has not started generating the power supply voltage. Therefore, the signal b is not output from the voltage monitoring unit 113, and the power supply IC 120 has not started generating the power supply voltage.

  At time t1, when the voltage value detected by the power-on reset unit 107 reaches a predetermined voltage value, the power-on reset unit 107 outputs an operation start signal to the DC / DC converter unit 102 and the timer unit 109. To do.

  The DC / DC converter unit 102 that has received the operation start signal output from the power-on reset unit 107 starts generating the power supply voltage. As a result, the voltage value of the power supply voltage output from the power supply IC 100 increases.

  The timer unit 109 that has received the operation start signal output from the power-on reset unit 107 activates the timer.

  When the power supply voltage output from the power supply IC 100 at time t <b> 2 becomes higher than the voltage value determined in advance according to the voltage value set in the power supply IC 100, the voltage monitoring unit 113 outputs the signal b to the power supply IC 120. Start output.

  The power supply IC 120 that has received the signal b output from the voltage monitoring unit 113 starts generating a power supply voltage. As a result, the voltage value of the power supply voltage output from the power supply IC 120 increases.

  In this way, a sequence is started in which the output of the power supply voltage of 1.2 V from the power supply IC 100 to the SOC 20 is started, and then the output of the power supply voltage of 3.3 V from the power supply IC 120 to the SOC 20 is started.

  In the state where the power supply voltage is not output from the power supply IC 120 immediately after the power supply of the power supply system 10 is turned on, the timer unit 109 outputs a reset state signal to the resetout terminal 110. At this time, since the reset-out signal is not output from the reset-out terminal 110, the signal c is not output from the gate 112, and the switch 111 is in an OFF state. Therefore, the power supply IC 100 can generate the power supply voltage regardless of the voltage value of the power supply voltage output from the power supply IC 120.

  The timer unit 109 starts outputting the reset release state signal to the reset-out terminal 110 after a predetermined time has elapsed since the timer was started. Thereby, output of the reset-out signal from the reset-out terminal 110 is started at time t3.

  Next, an operation when an abnormality occurs in the power supply voltage output from the power supply IC 100 which is the first power supply IC after the output of the power supply voltage in the power supply system shown in FIG.

  FIG. 3 is a timing chart for explaining the operation when an abnormality occurs in the power supply voltage output from the first power supply IC after the output of the power supply voltage is started in the power supply system 10 shown in FIG. is there.

  When an abnormality occurs in the power supply voltage output from the power supply IC 100 at time t4, the voltage value of the divided voltage a changes. At this time, if the difference between the voltage value of the divided voltage a and a predetermined reference voltage value is equal to or greater than a predetermined value, the abnormality detection unit 105 determines that some abnormality has occurred. Then, the abnormality detection unit 105 outputs an abnormality detection signal to the stop holding unit 104.

  The stop holding unit 104 that has received the abnormality detection signal output from the abnormality detection unit 105 starts outputting the first stop instruction signal to the switching unit 103. At the same time, the stop holding unit 104 outputs a second stop instruction signal to the timer unit 109.

  The switching unit 103 that has received the first stop instruction signal output from the stop holding unit 104 stops switching.

  In addition, the timer unit 109 that has received the second stop instruction signal output from the stop holding unit 104 stops outputting the reset release state signal and outputs the reset state signal to the reset-out terminal 110. As a result, the output of the reset-out signal from the reset-out terminal 110 is stopped.

  When the switching unit 103 stops switching, the voltage value of the power supply voltage output from the power supply IC 100 decreases.

  The voltage monitoring unit 113 stops the output of the signal b when the voltage value of the power supply voltage output from the power supply IC 100 drops below a value determined in advance according to the voltage value set in the power supply IC100. As a result, the power supply IC 120 stops generating the power supply voltage.

  Thus, when an abnormality occurs in the power supply voltage output from the power supply IC 100, the output of the power supply voltage from both of the power supply ICs 100 and 120 can be stopped. Note that this state is maintained as long as the first stop instruction signal is output from the stop holding unit 104 to the switching unit 103. That is, this state is maintained unless the power supply of the power supply system 10 is once cut off.

  Next, an operation when an abnormality occurs in the power supply voltage output from the power supply IC 120 as the second power supply IC after the output of the power supply voltage in the power supply system 10 shown in FIG. 1 is started will be described.

  FIG. 4 is a timing chart for explaining the operation when an abnormality occurs in the power supply voltage output from the second power supply IC after the output of the power supply voltage is started in the power supply system 10 shown in FIG. is there.

  When an abnormality occurs in the power supply voltage output from the power supply IC 120 and the voltage value drops below a predetermined value according to the voltage value set in the power supply IC 120 at time t5, the gate 112 switches the signal c. To 111. This is because a reset-out signal flows through the signal line 13. As a result, the switch 111 is turned on. As a result, an external current flows into the connection point between the resistor 114 and the resistor 115, and the voltage value of the divided voltage a increases.

  When the difference between the voltage value of the divided voltage a and the predetermined reference voltage value becomes equal to or greater than the predetermined value at time t6, the abnormality detection unit 105 determines that some abnormality has occurred. Then, the abnormality detection unit 105 outputs an abnormality detection signal to the stop holding unit 104.

  The stop holding unit 104 that has received the abnormality detection signal output from the abnormality detection unit 105 starts outputting the first stop instruction signal to the switching unit 103. At the same time, the stop holding unit 104 outputs a second stop instruction signal to the timer unit 109.

  The switching unit 103 that has received the first stop instruction signal output from the stop holding unit 104 stops switching.

  In addition, the timer unit 109 that has received the second stop instruction signal output from the stop holding unit 104 stops outputting the reset release state signal and outputs the reset state signal to the reset-out terminal 110. As a result, the output of the reset-out signal from the reset-out terminal 110 is stopped.

  When the switching unit 103 stops switching, the voltage value of the power supply voltage output from the power supply IC 100 decreases.

  The voltage monitoring unit 113 stops the output of the signal b when the voltage value of the power supply voltage output from the power supply IC 100 drops below a value determined in advance according to the voltage value set in the power supply IC100. As a result, the power supply IC 120 stops generating the power supply voltage.

  As described above, when an abnormality occurs in the power supply voltage output from the power supply IC 120, the output of the power supply voltage from both of the power supply ICs 100 and 120 is performed as in the case where an abnormality occurs in the power supply voltage output from the power supply IC 100. Can be stopped. Note that this state is maintained as long as the first stop instruction signal is output from the stop holding unit 104 to the switching unit 103. That is, this state is maintained unless the power supply of the power supply system 10 is once cut off.

  As is apparent from the above description, the switch 111 changes the voltage value of the divided voltage a, which is the voltage at the connection point between the resistor 114 and the resistor 115, to a level that the abnormality detection unit 105 determines to be abnormal. Is provided.

  Here, the reason why the voltage value of the divided voltage a is increased when the switch 111 is in the ON state is as follows.

  When the voltage value of the divided voltage a is increased, the operation of the power supply IC 100 is performed when the voltage value of the power supply voltage output from the power supply IC100 is higher than the voltage value (1.2 V) set in the power supply IC100. become. That is, the power supply IC 100 operates so as to reduce the voltage value of the generated power supply voltage, and generation of the power supply voltage is stopped when the abnormality detection unit 105 determines that an abnormality has occurred.

  If the voltage value of the divided voltage a is reduced when the switch 111 is on, for example, if one end of the switch 111 is connected to GND (ground), the switch 111 is on. Then, the voltage value of the divided voltage a decreases. Therefore, the operation of the power supply IC 100 is an operation when the voltage value of the power supply voltage output from the power supply IC100 is lower than the voltage value (1.2 V) set in the power supply IC. That is, the power supply IC 100 operates so as to increase the voltage value of the power supply voltage. In this case, the voltage value of the power supply voltage output from the power supply IC 100 becomes higher than 1.2 V, and the allowable voltage value of the SOC 20 may be exceeded before the generation of the power supply voltage is stopped. This is not desirable because it causes destruction and deterioration of the SOC 20.

  Therefore, in this embodiment, one end of the switch 111 accepts a voltage of 24 V output from the outside, and the voltage value of the divided voltage a is increased when the switch 111 is in an on state. That is, one end of the switch 111 is connected to a voltage source higher than the voltage value set in the power supply IC 100.

  As described above, in this embodiment, the power supply system 10 includes the divided voltage generation unit that generates the divided voltage a obtained by dividing the power supply voltage output from the power supply IC 100, and the voltage value of the power supply voltage output from the power supply IC100. And a voltage monitoring unit 113 for detection.

  Further, the power supply system 10 detects the voltage value of the power supply voltage output from the power supply IC 120, and when the detected voltage value falls below a predetermined value according to the voltage value set in the power supply IC 120, A divided voltage adjustment unit that changes the voltage value of the divided voltage a is provided.

  Then, the power supply IC 100 detects the voltage value of the divided voltage a, and stops the generation of the power supply voltage when the difference between the detected voltage value and the predetermined reference voltage value is equal to or greater than the predetermined value.

  Further, the power supply IC 120 stops generating the power supply voltage when the voltage value detected by the voltage monitoring unit 113 falls below a value determined in advance according to the voltage value set in the power supply IC100.

  Thereby, when an abnormality occurs in any one of the power supply systems of the plurality of power supply ICs without complicating the configuration, the operations of all the plurality of power supply ICs can be stopped.

  In the present embodiment, the case where the second power supply IC is only one of the power supply ICs 120 has been described. However, even when there are two or more second power supply ICs, the above-described operation and effect can be realized. it can. In this case, gates 112 corresponding to the number of second power supply ICs are prepared, and the power supply voltages output from the second power supply ICs can be received by the gates 112 corresponding to the second power supply ICs. do it. Thus, even when an abnormality occurs in any of the two or more second power supply ICs, the operations of the plurality of power supply ICs can be stopped.

The power supply system according to the power control apparatus according to the present invention is not limited to the configuration shown in FIG.

Figure 5 is a block diagram for explaining a configuration of another embodiment of a power supply system according to the power control apparatus according to the present invention.

  When the power supply system 10 shown in FIG. 1 is compared with the power supply system 10-1 shown in FIG. 5, in the power supply system 10-1 shown in FIG. 5, the switch 111 and the gate 112 in the power supply system 10 shown in FIG. Is different from that of a transistor.

  As shown in FIG. 5, by using a transistor with a built-in resistor as the transistors 118a to 118c, the same operation as the power supply system 10 shown in FIG. 1 can be realized with a very small number of components.

10, 10-1 Power system 11, 12 Output line 13 Signal line 20 SOC
100,120 Power IC
DESCRIPTION OF SYMBOLS 101 Internal power supply part 102 DC / DC converter part 103 Switching part 104 Stop holding part 105 Abnormality detection part 106 Voltage detection part 107 Power-on reset part 108 Oscillation part 109 Timer part 110 Reset out terminal 111 Switch 112 Gate 113 Voltage monitoring part 114, 115 Resistor 116 Coil 117 Capacitor 118 a to c Transistor 121 Enable terminal 201, 202 Power supply terminal 203 Reset terminal

Claims (5)

A power supply control device that causes a second power supply circuit other than the first power supply circuit to generate a power supply voltage of a predetermined voltage value while the first power supply circuit outputs a power supply voltage of a predetermined voltage value to the SOC. There,
Switch signal control means for changing the switch signal to switch the switch to an on state;
Whether the difference between the voltage value of the power supply voltage output from the first power supply circuit and the predetermined voltage value is greater than or equal to a predetermined value by detecting a signal based on the power supply voltage output from the first power supply circuit Determination means for determining;
Generation of power supply voltage by the first power supply circuit when the determination means determines that the difference between the voltage value of the power supply voltage output from the first power supply circuit and a predetermined voltage value is greater than or equal to a predetermined value First stopping means for stopping
If generation of the supply voltage to the first power supply circuit is stopped, it has a second stop means for stopping the generation of the supply voltage by the second power supply circuit,
By switching the switch to the ON state by the switch signal, the determination unit determines that the difference between the detected voltage value and the predetermined voltage value is greater than or equal to a predetermined value. Stopping generation of power supply voltage by the first power supply circuit;
The SOC is operated by detecting a signal indicating a reset release state after a lapse of a predetermined time required for the first and second power supply circuits to output a power supply voltage having a predetermined voltage value,
The switch signal control means switches a switch when a signal indicating the reset release state after the lapse of the predetermined time is detected and the voltage value output from the second power supply circuit is determined to be equal to or less than a threshold value. A power supply control device that changes a switch signal to switch to an on state . Divided voltage generation means for generating a divided voltage obtained by dividing the power supply voltage output from the first power supply circuit;
The determination unit determines whether a difference between the divided voltage generated by the divided voltage generation unit and a predetermined voltage value is equal to or greater than a predetermined value;
2. The divided voltage generated by the divided voltage generation unit is changed when it is determined that the voltage value of the power supply voltage output from the second power supply circuit is equal to or less than a threshold value. The power supply control device described in 1. Control means for controlling the first power supply circuit to generate a power supply voltage having a predetermined voltage value based on a result of detecting a signal based on the power supply voltage output from the first power supply circuit. The power supply control device according to claim 1 or 2 . The switch power supply control device according to any one of claims 1 to 3, characterized in that it is constituted by a transistor. 2. A voltage having a value larger than a value of a power supply voltage generated by the first and second power supply circuits is supplied when the switch is turned on by the switch signal. 5. The power supply control device according to any one of items 1 to 4.

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