JP6201775B2 - Information processing apparatus, power supply control circuit, and AC adapter - Google Patents

Description

  The present invention relates to an information processing apparatus, a power supply control circuit, and an AC adapter.

  Conventionally, when charging a battery of an information processing apparatus, charging is performed using a charging current controlled at a constant current by an AC adapter at the beginning of charging, and charging is performed using a charging current controlled at a constant voltage by a charging circuit at the end of charging. The technique to do is known (for example, refer patent document 1).

Japanese Patent Application Laid-Open No. 10-191577

  However, in the above-described conventional technology, when charging with constant current control, the constant current output from the AC adapter is used as it is as the charging current of the battery, so the current value of the constant current output from the AC adapter is The charging current is fixed to the current value. For this reason, when the current consumption of the information processing apparatus temporarily increases during charging with constant current control, the output voltage of the AC adapter may decrease.

  Therefore, an object of the present invention is to provide an information processing apparatus, a power supply control circuit, and an AC adapter that can suppress a decrease in the output voltage of the AC adapter during battery charging.

One idea is that
An information processing apparatus including a battery charged by a DC output output from an AC adapter,
A charging circuit for charging the battery at a constant voltage based on the DC output;
Wherein the power supply state of the information processing apparatus is changed from OFF to ON, and a power supply control circuit for switching the overcurrent protection characteristics inverted L-shape characteristics from the off-characteristic of the AC adapter,
The power control circuit switches the charging path of the battery to a circuit path via the charging circuit when the power state changes from off to on, and changes the charging path when the power state changes from on to off. An information processing apparatus is provided that switches to a bypass path that bypasses a charging circuit, and switches the charging path to the circuit path when the battery voltage of the battery reaches a set value when the charging path is the bypass path. .

  According to one aspect, it is possible to suppress the output voltage of the AC adapter from decreasing during battery charging.

Configuration diagram showing an example of an information processing apparatus The figure which shows an example of a reverse L character characteristic Diagram showing an example of the U-characteristic Configuration diagram showing an example of an AC adapter Table showing an example of charging path switching method The figure which shows an example of the characteristic of charge voltage and charge current

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. “AC” represents alternating current, an abbreviation for “Alternating Current”, and “DC” represents direct current, an abbreviation for “Direct Current”.

  FIG. 1 is a configuration diagram illustrating an example of the information processing apparatus 200. The information processing apparatus 200 is an example of a computer including a battery 51 that is charged by a DC output output from the AC adapter 100. A specific example of the information processing apparatus 200 is a portable personal computer (PC). The information processing apparatus 200 includes a battery 51, a load 55, and a power supply control circuit 52.

  The battery 51 is an example of a secondary battery that is charged by a DC output output from the AC adapter 100. A specific example of the battery 51 is a lithium ion battery. The battery 51 is, for example, a battery pack that is replaceably attached to the information processing apparatus 200.

  The load 55 is one or more devices that operate using a DC voltage output from the battery 51 or the AC adapter 100 as a power supply voltage. DC power supplied from the battery 51 or the AC adapter 100 is consumed by the operation of the load 55. Specific examples of the load 55 include a central processing unit (CPU), a main storage device, an input / output circuit, an auxiliary storage device, a display device, a communication device, and a keyboard.

  The power supply control circuit 52 is an example of a power supply controller that switches overcurrent protection characteristics of the AC adapter 100 according to the power supply state of the information processing apparatus 200. The power supply control circuit 52 may also be included as one of the loads 55. The power supply control circuit 52 may be a power supply control microcomputer or a simple logic circuit.

  FIG. 2 is a diagram illustrating an example of an inverted L-characteristic that is one of the overcurrent protection characteristics of the AC adapter 100, and FIG. 3 is a F-characteristic that is one of the overcurrent protection characteristics of the AC adapter 100. It is a figure which shows an example. “Fu” is one of the Japanese katakana characters. The overcurrent protection characteristic of the AC adapter 100 is an output characteristic that determines a characteristic curve of the DC output of the AC adapter 100, and is a transition state represented by the relationship between the output current Iad and the output voltage Vad at the DC output. 2 and 3 are characteristic diagrams in which the horizontal axis represents the output current Iad (arbitrary unit) and the vertical axis represents the output voltage Vad (arbitrary unit).

  The reverse L-shaped characteristic of FIG. 2 is that when the output current Iad is about to exceed the predetermined rated current value I1 at the overcurrent protection point b when the output voltage Vad is the predetermined rated voltage value V2, the output current Iad is It has a CC / CV characteristic in which the output voltage Vad decreases with the constant rated current value I1. The CC / CV characteristic is an abbreviation for a constant current / constant voltage characteristic. In other words, the inverted L-shaped characteristic is such that the output voltage Iad is maintained at a constant rated voltage value V2 and the output voltage Iad changes, and the output current Iad is maintained at a constant rated current value I1. And a constant current region in which the voltage Vad changes.

  In the case of FIG. 2, when the output voltage Vad decreases to the voltage value V1 of the overcurrent protection point a, the output voltage Vad decreases together with the output current Iad. The output voltage Vad decreases linearly to 0V, and the output current Iad also decreases linearly to 0A.

  When the AC adapter 100 performs DC output according to the inverted L-characteristic, the output current Iad can flow up to a predetermined rated current value I1 while suppressing a decrease in the output voltage Vad to a predetermined decrease amount. When the output current Iad exceeding the rated current value I1 is about to flow, an overcurrent protection function that reduces the output voltage Vad while the rated current value I1 is maintained can be activated.

  The F-shaped characteristic of FIG. 3 indicates that when the output current Iad tries to flow beyond the predetermined peak current value I3 at the overcurrent protection point c when the output voltage Vad is the predetermined rated voltage value V3, the output voltage Vad is It has a foldback characteristic that decreases with the output current Iad. In the case of FIG. 3, the output voltage Vad decreases linearly to 0V, and the output current Iad also decreases linearly to 0A.

  When the AC adapter 100 outputs DC according to the U-characteristic, the output current Iad is larger than the predetermined rated current value I2 by a time width of about several ms while suppressing the decrease in the output voltage Vad to a predetermined decrease amount. It can flow up to the peak current value I3. When the output current Iad exceeding the peak current value I3 is about to flow, an overcurrent protection function that decreases until the output voltage Vad and the output current Iad are forced to zero can be activated. The rated current value I2 may be equal to the rated current value I1 having an inverted L-shaped characteristic.

  In FIG. 1, the load 55 can operate when the power state of the information processing apparatus 200 is on, and the load 55 cannot operate when the power state of the information processing apparatus 200 is off. Therefore, when the power state of the information processing apparatus 200 is on, the current consumption of the load 55 may temporarily increase due to the operation of the load 55 depending on the operation mode of the load 55. When the current consumption of the load 55 is temporarily increased, the current consumption of the entire information processing apparatus 200 is also temporarily increased, and thus the output voltage Vad may be temporarily decreased.

  Therefore, when it is detected that the power state of the information processing apparatus 200 changes from off to on, the power supply control circuit 52 changes the overcurrent protection characteristic of the AC adapter 100 from the inverse L-characteristic (FIG. 2) to the Switch to characteristics (Fig. 3). On the other hand, when the power supply control circuit 52 detects that the power state of the information processing device 200 changes from on to off, the power supply control circuit 52 changes the overcurrent protection characteristic of the AC adapter 100 from the F-characteristic (FIG. 3) to the inverted L-character. Switch to characteristics (Fig. 2).

  Therefore, when the power state of the information processing apparatus 200 is on, the AC adapter 100 can charge the battery 51 in accordance with the U-characteristic. Therefore, even if the current consumption of the load 55 temporarily increases and the current consumption of the information processing apparatus 200 as a whole also increases temporarily, the AC adapter 100 increases the output current Iad to the peak current value I3 (FIG. 3). Therefore, the output voltage Vad can be prevented from temporarily decreasing.

  As a case where the current consumption of the load 55 temporarily increases, for example, a CPU that is one of the loads 55 operates in a turbo mode that performs very high speed processing by rapidly increasing a clock or the like for a short time. There are cases. Since the AC adapter 100 outputs DC according to the F-characteristic, peak power that can be used for a CPU that operates in the turbo mode can be supplied, so that the information processing apparatus 200 can be operated efficiently.

  On the other hand, when the power state of the information processing apparatus 200 is the off state, the power consumption of the load 55 does not increase temporarily. Therefore, AC adapter 100 can suppress a temporary decrease in output voltage Vad even when battery 51 is charged by performing constant current control according to a constant rated current value I1 defined by the inverted L-shaped characteristic. . It is preferable that the rated current value I1 (that is, the constant current value of the charging current of the battery 51) during the constant current control is set to the maximum charging current value defined by the charging characteristics of the battery 51.

  The current value (peak current value I3) at the output voltage droop point of the U-shaped characteristic is preferably set larger than the current value (rated current value I1) at the output voltage droop point of the inverted L-characteristic. Since the peak current value I3 is larger than the rated current value I1, the AC adapter 100 can output the output current Iad up to the peak current value I3 having a larger current value than the rated current value I1. It is possible to reliably suppress the output voltage Vad from being lowered due to a general rise. Further, it is possible to prevent the overcurrent protection characteristics of both the F-shaped characteristics and the inverted L-shaped characteristics from competing.

  In FIG. 2, the constant rated voltage value V2 may have a predetermined fluctuation range. For example, the rated voltage value V2 may fluctuate by 19V ± 10%. Similarly, the constant rated current value I1 may have a predetermined fluctuation range. For example, the rated current value I1 may fluctuate by 5A ± 2%. In FIG. 3, when the DC output rating of the AC adapter 100 is 100 W (= V3 × I2 = 19V × 5.27 A), the AC adapter 100 is 120 W (= V3 × I3 = 19 V × 6.32 A). The peak power can be output instantaneously.

  In FIG. 1, the power supply control circuit 52 includes a detection unit 53 and a transmission unit 54.

  The detection unit 53 is an example of a unit that detects on / off of the power state of the information processing apparatus 200. The detection unit 53 is a circuit that detects that the power state of the information processing device 200 changes from off to on and detects that the power state of the information processing device 200 changes from on to off.

  For example, the detection unit 53 may detect that the power state of the information processing device 200 changes from off to on by detecting an on operation that changes the power state of the information processing device 200 from off to on. Conversely, the detection unit 53 may detect that the power state of the information processing device 200 changes from on to off by detecting an off operation that changes the power state of the information processing device 200 from on to off. .

  The detection unit 53 detects, for example, a power switch operation, a mouse operation, or a keyboard operation for turning on / off the power of the information processing device 200, thereby detecting an on operation or an off operation of the power state of the information processing device 200. It's okay. In addition, the detection unit 53 may detect an ON operation or an OFF operation of the power state of the information processing apparatus 200 by monitoring an operating state of an OS (Operating System) processed by the CPU, for example.

  Further, the detection unit 53 may detect a change between the on state and the shutdown state with respect to the power state of the information processing apparatus 200, or detect a change between the on state and the hibernation state. Alternatively, a change between the on state and the suspended state may be detected.

  The shutdown state is a state in which the operation of the OS is finished and power supply to the load 55 is stopped. The hibernation state (hibernation state) is a state in which the operation content of the main storage device is stored in an auxiliary storage device such as a hard disk and power supply to the load 55 is stopped. The suspended state (sleep state) is a state in which power supply to the main storage device is continued and power supply to the unused load 55 is stopped.

  The shutdown state, hibernation state, and suspend state all indicate that the power state of the information processing apparatus 200 is off. That is, the off state is not limited to one state, and may be divided into a plurality of states.

  The transmission unit 54 transmits a control signal for switching overcurrent protection characteristics of the AC adapter 100 to the AC adapter 100 connected to the information processing device 200 according to the power state of the information processing device 200 detected by the detection unit 53. It is an example of the means to do. When the detection unit 53 detects that the power state of the information processing apparatus 200 changes from off to on, the transmission unit 54 switches the overcurrent protection characteristic of the AC adapter 100 from the inverted L-characteristic to the F-characteristic. A control signal Sig0 is transmitted. On the other hand, when the detection unit 53 detects that the power state of the information processing device 200 changes from on to off, the transmission unit 54 changes the overcurrent protection characteristic of the AC adapter 100 from the F-characteristic to the inverted L-characteristic. A control signal Sig0 for switching to is transmitted.

  FIG. 4 is a configuration diagram illustrating an example of the AC adapter 100. The AC adapter 100 is an example of a power supply device that converts an AC input into a DC output and outputs the DC output. The AC adapter 100 includes an output circuit 60, a switching circuit 70, and an overcurrent protection circuit that determines overcurrent protection characteristics of the output circuit 60.

  The output circuit 60 is an example of a circuit that outputs a DC output for charging the battery 51 of the information processing apparatus 200. The output circuit 60 includes a PWM (Pulse Width Modulation) control unit 10, a transformer 20, and a smoothing circuit 21.

  The PWM control unit 10 is a circuit that performs PWM control of the primary current flowing in the primary side coil of the transformer 20. The PWM control unit 10 includes a rectifier circuit 11 and an oscillation circuit 12. The rectifier circuit 11 is a circuit that converts alternating current into direct current and applies the converted direct current voltage to both ends of the primary side coil of the transformer 20. The oscillation circuit 12 is a circuit that operates with the power supply voltage Vcc generated from the primary side coil of the transformer 20 and determines the control frequency of the PWM control. The smoothing circuit 21 outputs DC power obtained by smoothing the power output from the secondary side coil of the transformer 20. The output power of the smoothing circuit 21 is the DC output of the AC adapter 100.

  The switching circuit 70 is an example of a circuit that switches overcurrent protection characteristics of the output circuit 60 in accordance with the power supply state of the information processing apparatus 200. The switching circuit 70 includes a resistor R6, a resistor R7, and a switch SW3. The switch SW3 is an N-channel MOS (Metal Oxide Semiconductor) transistor.

  A series circuit of a resistor R6 and a resistor R7 is disposed between the DC output line and the internal ground of the AC adapter 100. The gate of the switch SW3 is connected to an intermediate connection point between the resistor R6 and the resistor R7, and the control signal Sig0 transmitted from the information processing apparatus 200 is input. The drain of the switch SW3 is connected to a ground line 0V (GND) that connects the AC adapter 100 and the information processing apparatus 200. The ground line 0V (GND) is a reference line for DC output. The source of the switch SW3 is connected to one side of the resistor R9 provided at the input portion of the inverted L-shaped characteristic circuit 40.

  When the switching circuit 70 receives the control signal Sig0 for switching the overcurrent protection characteristic of the AC adapter 100 from the inverted L-characteristic to the F-characteristic, the switching circuit 70 changes the overcurrent protection circuit that limits the DC output of the output circuit 60 to the inverse L-character The characteristic circuit 40 is switched to the U-shaped characteristic circuit 30. Thereby, the overcurrent protection characteristic of the AC adapter 100 can be switched from the inverted L-characteristic to the F-characteristic.

  On the other hand, when the switching circuit 70 receives the control signal Sig0 for switching the overcurrent protection characteristic of the AC adapter 100 from the F-characteristic to the inverted L-characteristic, The character circuit 30 is switched to the inverted L-characteristic circuit 40. Thereby, the overcurrent protection characteristic of the AC adapter 100 can be switched from the F-characteristic to the inverted L-characteristic.

  The inverse L-characteristic circuit 40 is an overcurrent protection circuit that transitions the DC output output from the output circuit 60 according to the inverse L-characteristic. The U-shaped characteristic circuit 30 is an overcurrent protection circuit that transitions the DC output output from the output circuit 60 according to the U-shaped characteristics.

  When the power supply state of the information processing apparatus 200 is in the off state, the switching circuit 70 receives the low-level control signal Sig0 indicating the off state, and turns on the switch SW3 whose drain is connected to the ground line 0V (GND). (ON state). When the switch SW3 is turned on, the voltage drop level of the load current detection resistor R8 can be detected. The load current is a current that flows from the output circuit 60 to the DC output line, and flows to the ground line 0V (GND) via the information processing apparatus 200. The detection resistor R8 is a resistor inserted in series with the ground line 0V (GND) between the connection point where the drain of the switch SW3 and the ground line 0V (GND) are connected and the output circuit 60.

  As the load current increases, the voltage drop level due to the detection resistor R8 increases, and the potential of the inverting input terminal of the operational amplifier OP1 increases. The inverting input terminal of the operational amplifier OP1 is connected to a connection point where one end of the resistor R9 and one end of the capacitor C1 are connected. The other end of the resistor R9 is connected to the source of the switch SW3, and the other end of the capacitor C1 is connected to the internal ground of the AC adapter 100.

  When the potential of the inverting input terminal of the operational amplifier OP1 exceeds the reference potential of the non-inverting input terminal of the operational amplifier OP1, a feedback signal for maintaining the non-inverting input terminal and the inverting input terminal of the operational amplifier OP1 at the same potential is output from the operational amplifier OP1. Is output. The reference potential of the non-inverting input terminal of the operational amplifier OP1 is determined by the resistors R10, R11, R12 and the Zener diode ZD2.

  The feedback signal output from the operational amplifier OP <b> 1 is given to the primary side PWM control unit 10 via the photocoupler 22. If the load current is increased in order to keep the input terminal of the operational amplifier OP1 at the same potential, a feedback signal having a higher signal level is transmitted to the PWM control unit 10, so that the output voltage Vad decreases. That is, overcurrent protection according to the inverted L-characteristic defined by the inverted L-characteristic circuit 40 functions.

  On the other hand, when the power state of the information processing apparatus 200 is the on state, the switching circuit 70 receives the high-level control signal Sig0 indicating the on state, and switches the switch SW3 whose drain is connected to the ground line 0V (GND). Set to the open state (off state). When the switch SW3 is turned off, the voltage drop level due to the load current detection resistor R8 cannot be detected. As a result, the overcurrent protection function according to the U-shaped characteristic defined by the U-shaped characteristic circuit 30 functions based on the primary side current of the transformer 20 detected by the current detecting unit 23. That is, it is possible to output a DC output that increases to a peak current corresponding to the supply capability of the primary-side PWM control unit 10.

  In FIG. 1, the information processing apparatus 200 includes a charging circuit 50. The charging circuit 50 is an example of a circuit that charges the battery 51 with a constant voltage based on the DC output supplied from the AC adapter 100. The charging circuit 50 steps down the DC output of the AC adapter 100 and supplies the reduced charging power to the battery 51.

  The power supply control circuit 52 switches the charging path for charging the battery 51 to the circuit path via the charging circuit 50 when it is detected that the power supply state of the information processing apparatus 200 changes from off to on. On the other hand, when it is detected that the power state of the information processing apparatus 200 changes from on to off, the power supply control circuit 52 switches the charging path for charging the battery 51 to the bypass path for bypassing the charging circuit 50.

  FIG. 5 is a table showing an example of a method for switching the charging path of the battery 51. The operation of the switches SW1 and SW2 in FIG. 1 will be described according to the table in FIG. Each of the switches SW1 and SW2 is a P-channel MOS transistor, the switch SW1 has a resistance R1 between the gate and the source, and the switch SW2 has a resistance R2 between the gate and the source.

  When the power supply state of the information processing apparatus 200 is on, the power supply control circuit 52 sets the gate signal Sig1 of the switch SW1 to low level to turn on the switch SW1, and sets the gate signal Sig2 of switch SW2 to high level or open. The switch SW2 is opened. By making the switch SW1 conductive and the switch SW2 open, the charging path of the battery 51 is a path from the AC adapter 100 to the battery 51 via the switch SW1, the charging circuit 50, and the diode D1. Since the charging path of the battery 51 becomes a circuit path via the charging circuit 50, the charging circuit 50 can step down the DC output of the AC adapter 100 to generate a constant charging voltage, and the constant charging voltage can be set to the constant charging voltage. The battery 51 can be supplied with the controlled charging current.

  Further, when the power supply state of the information processing apparatus 200 is on, the power supply control circuit 52 sets the control signal Sig0 to high level or open, so that the DC output of the AC adapter 100 is in accordance with the U-characteristic (see FIG. 3). It is supplied to the charging circuit 50 of the information processing apparatus 200. Therefore, even if the peak power at the overcurrent protection point c having the U-shaped characteristic is supplied to the information processing apparatus 200, the charging circuit 50 can convert the peak power into charging power controlled at a constant voltage. That is, the peak power can be prevented from being supplied to the battery 51 as it is.

  On the other hand, when the power supply state of the information processing apparatus 200 is OFF, the power supply control circuit 52 sets the gate signal Sig1 of the switch SW1 to a high level or open to open the switch SW1, and sets the gate signal Sig2 of the switch SW2 to low. At a level, the switch SW2 is turned on. By making switch SW1 open and making switch SW2 conductive, the charging path of battery 51 is a path from AC adapter 100 to battery 51 via switch SW2 and diode D1. Since the charging path of the battery 51 becomes a bypass path that bypasses the charging circuit 50, the charging circuit 50 cannot charge the battery 51, and the AC adapter 100 quickly charges the battery 51 with DC output without going through the charging circuit 50. it can.

  Further, when the power supply state of the information processing apparatus 200 is in the off state, the power supply control circuit 52 sets the control signal Sig0 to the low level, so that the DC output of the AC adapter 100 performs information processing according to the inverse L-characteristic (see FIG. 2). It is supplied to the battery 51 of the device 200. Therefore, the AC adapter 100 can supply the output current Iad according to the inverted L-characteristic as the charging current of the battery 51, and can quickly charge the battery 51.

  In the U-shaped characteristic, the peak current value I3 of the overcurrent protection point c is set to, for example, about 1.5 times the rated current value I2 of the continuous rated current, and for example, 10 ms for preventing malfunction of overcurrent protection due to external noise. A response delay time of about is set. That is, an instantaneous load current within 10 ms can correspond to a peak current during operation of the information processing apparatus 200 while keeping the output voltage Vad within a predetermined accuracy. However, the charging time of the battery 51 is naturally longer than the transient time of the peak load. Therefore, when the overcurrent protection characteristic is switched to the inverted L-characteristic, the battery 51 can be rapidly charged with the maximum rated current value I1 of the continuous rated current by making the best use of the output capacity of the AC adapter 100. Furthermore, since the overcurrent protection characteristic is switched to the inverted L-characteristic, the battery 51 can be charged without going through the charging circuit 50, so that loss due to going through the charging circuit 50 can be reduced.

  When the efficiency of the charging circuit 50 is, for example, about 90%, for example, a heat loss of about 10% has occurred. Therefore, loss can be reduced by performing quick charging directly from the AC adapter 100. Further, by performing rapid charging from the AC adapter 100, it is possible to prevent the charging circuit 50 from becoming large and increasing its number of parts.

  Further, when the power state of the information processing device 200 is on, peak power corresponding to the turbo mode of the CPU can be supplied, and when the power state of the information processing device 200 is off, it does not go directly through the charging circuit 50. The battery 51 can be quickly charged from the AC adapter 100. As a result, the AC adapter 100 can be prevented from being enlarged.

  In FIG. 1, the comparator CP1 is a means for detecting that the battery voltage Vbatt of the battery 51 has risen to reach a set value (for example, 12.6V) when the power state of the information processing apparatus 200 is OFF. is there. When the power supply state of the information processing apparatus 200 is in the off state, the charging path of the battery 51 is a bypass path that bypasses the charging circuit 50. Therefore, the DC output of the AC adapter 100 is directly supplied to the battery 51 via the diode D2, and the battery 51 is rapidly charged according to the inverted L-characteristic.

  The reference voltage Vref generated by the resistor R3 and the Zener diode ZD1 is input to one input terminal of the comparator CP1, and the resistance divided value of the battery voltage Vbatt by the resistors R4 and R5 is input to the other input terminal. Entered. When the battery voltage Vbatt rises and the resistance voltage division value exceeds the reference voltage Vref, the output of the comparator CP1 is inverted, and the inversion result is transmitted to the power supply control circuit 52. When the inversion of the comparator CP1 (that is, the battery voltage Vbatt has reached the set value) is detected, the power supply control circuit 52 opens the switch SW2 and turns on the switch SW1. When the switch SW2 is opened and the switch SW1 is turned on, the charging path of the battery 51 becomes a circuit path via the charging circuit 50. Therefore, the charging circuit 50 charges the battery 51 by constant voltage control using the set value as a constant voltage value.

  FIG. 6 is a diagram illustrating an example of the characteristics of the charging voltage and the charging current over time of the battery 51. The vertical axis represents voltage or current, and the horizontal axis represents time. The unit of the vertical axis and the horizontal axis is arbitrary. When charging the battery 51 from the AC adapter 100 when the power state of the information processing apparatus 200 is off, the overcurrent protection characteristic of the AC adapter 100 is an inverted L-characteristic, and therefore the rated output current of the AC adapter 100 is Constant current charging starts at the rated current value I7. That is, the rated current value I7 is equal to the rated current value I1 in FIG.

  In FIG. 6, the battery voltage Vbatt rises with time from the discharge end voltage V5 to the charge upper limit voltage V6 (set value) according to the amount of charge. When the comparator CP1 detects that the battery voltage Vbatt has reached the charging upper limit voltage V6, the power supply control circuit 52 switches from a path that bypasses the charging circuit 50 to a path that passes through the charging circuit 50.

  By switching to a path that passes through the charging circuit 50, the charging circuit 50 charges the battery 51 at a constant voltage by constant voltage control using the charging upper limit voltage V6 as a constant voltage value. When the battery 51 is charged at a constant voltage, the current value of the charging current of the battery 51 is reduced to a current value I8 and becomes low.

  As described above, the information processing apparatus, the power supply control circuit, and the AC adapter have been described according to the embodiments. However, the present invention is not limited to the above embodiments. Various modifications and improvements such as combinations and substitutions with some or all of the other embodiments are possible within the scope of the present invention.

  For example, the information processing apparatus may be portable or stationary. The information processing apparatus may be a battery-driven electronic device other than a personal computer (for example, a mobile wireless terminal such as a mobile phone, a smartphone, or the like).

  For example, the transistor used is not limited to a MOS transistor, and other switching elements such as a bipolar transistor may be used.

Regarding the above embodiment, the following additional notes are disclosed.
(Appendix 1)
An information processing apparatus including a battery charged by a DC output output from an AC adapter,
A power supply control circuit that switches overcurrent protection characteristics of the AC adapter according to the power supply state of the information processing apparatus;
The information processing apparatus according to claim 1, wherein the power supply control circuit switches the overcurrent protection characteristic from an inverted L-characteristic to a F-characteristic when the power supply state changes from off to on.
(Appendix 2)
The information processing apparatus according to appendix 1, wherein a peak current value of the U-shaped characteristic is larger than a constant current value of the inverted L-shaped characteristic.
(Appendix 3)
A charging circuit for charging the battery at a constant voltage based on the DC output;
The information processing apparatus according to appendix 1 or 2, wherein the power control circuit switches the charging path of the battery to a circuit path that passes through the charging circuit when the power state changes from off to on.
(Appendix 4)
The information processing apparatus according to appendix 3, wherein the power supply control circuit switches the charging path to a bypass path that bypasses the charging circuit when the power state changes from on to off.
(Appendix 5)
The information processing apparatus according to appendix 4, wherein the power supply control circuit switches the charging path to the circuit path when the battery voltage of the battery reaches a set value when the charging path is the bypass path.
(Appendix 6)
A detection unit for detecting a power state of an information processing apparatus including a battery charged by a DC output output from an AC adapter;
A transmission unit that transmits a control signal for switching overcurrent protection characteristics of the AC adapter according to the power supply state detected by the detection unit;
The power transmission control circuit, wherein the transmission unit transmits a control signal for switching the overcurrent protection characteristic from an inverted L-characteristic to a F-characteristic when the power supply state changes from off to on.
(Appendix 7)
The power supply control circuit according to appendix 6, wherein a peak current value of the U-shaped characteristic is larger than a constant current value of the inverted L-shaped characteristic.
(Appendix 8)
The power supply according to appendix 6 or 7, wherein when the power state changes from off to on, the charging path of the battery is switched to a circuit path via a charging circuit that charges the battery with a constant voltage based on the DC output. Control circuit.
(Appendix 9)
The power supply control circuit according to appendix 8, wherein when the power state changes from on to off, the charging path is switched to a bypass path that bypasses the charging circuit.
(Appendix 10)
The power supply control circuit according to appendix 9, wherein when the battery path of the battery reaches a set value when the charging path is the bypass path, the charging path is switched to the circuit path.
(Appendix 11)
An output circuit for outputting a DC output for charging the battery of the information processing apparatus;
A switching circuit that receives a power state of the information processing device from the information processing device and switches overcurrent protection characteristics of the output circuit;
The AC adapter, wherein the switching circuit switches the overcurrent protection characteristic from an inverted L-characteristic to a F-characteristic when the power supply state changes from off to on.
(Appendix 12)
The AC adapter according to appendix 11, wherein a peak current value of the U-shaped characteristic is larger than a constant current value of the inverted L-shaped characteristic.

30 Characteristic Characteristic Circuit 40 Reverse L Characteristic Circuit 50 Charging Circuit 51 Battery 52 Power Supply Control Circuit 53 Detection Unit 54 Transmission Unit 60 Output Circuit 70 Switching Circuit 100 AC Adapter 200 Information Processing Device

Claims (7)

An information processing apparatus including a battery charged by a DC output output from an AC adapter,
A charging circuit for charging the battery at a constant voltage based on the DC output;
Wherein the power supply state of the information processing apparatus is changed from OFF to ON, and a power supply control circuit for switching the overcurrent protection characteristics inverted L-shape characteristics from the off-characteristic of the AC adapter,
The power control circuit switches the charging path of the battery to a circuit path via the charging circuit when the power state changes from off to on, and changes the charging path when the power state changes from on to off. An information processing apparatus that switches to a bypass path that bypasses a charging circuit, and switches the charging path to the circuit path when the battery voltage of the battery reaches a set value when the charging path is the bypass path . The information processing apparatus according to claim 1, wherein the power supply control circuit switches the overcurrent protection characteristic from a F-characteristic to an inverted L-characteristic when the power supply state changes from on to off. Peak current value of the shape characteristics of the marks, the larger than the constant current value of the inverted-L characteristic, the information processing apparatus according to claim 1 or 2. A detection unit for detecting a power state of an information processing apparatus including a battery charged by a DC output output from an AC adapter;
A transmission unit for transmitting a control signal for switching the overcurrent protection characteristic of the AC adapter from the inverted L-shaped characteristic to the F-shaped characteristic when the power supply state detected by the detecting unit changes from off to on ;
When the power state changes from off to on, the transmission unit transmits a signal for switching the charging path of the battery to a circuit path via a charging circuit that charges the battery with a constant voltage based on the DC output. When the power state changes from on to off, a signal for switching the charging path to a bypass path that bypasses the charging circuit is transmitted, and when the charging path is the bypass path, the battery voltage of the battery is set to a set value A power supply control circuit that transmits a signal for switching the charging path to the circuit path when reaching . 5. The power supply control circuit according to claim 4, wherein, when the power supply state changes from on to off, the transmission unit transmits a control signal for switching the overcurrent protection characteristic from a U-shaped characteristic to an inverted L-shaped characteristic. An output circuit for outputting a DC output for charging the battery of the information processing apparatus;
A switching circuit that receives a power state of the information processing device from the information processing device and switches overcurrent protection characteristics of the output circuit;
The information processing apparatus includes: a charging circuit that charges the battery with a constant voltage based on the DC output; and when the power supply state changes from off to on, the charging path of the battery is changed to a circuit path that passes through the charging circuit. When the power supply state changes from on to off, the charging path is switched to a bypass path that bypasses the charging circuit, and when the battery voltage of the battery reaches a set value when the charging path is the bypass path A power supply control circuit for switching the charging path to the circuit path,
The AC adapter, wherein the switching circuit switches the overcurrent protection characteristic from an inverted L-characteristic to a F-characteristic when the power supply state received from the information processing apparatus changes from off to on. The AC adapter according to claim 6, wherein the switching circuit switches the overcurrent protection characteristic from a U-shaped characteristic to an inverted L-shaped characteristic when the power state received from the information processing apparatus changes from on to off.

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