TW201742380A - Slew rate control apparatus, semiconductor apparatus, and electronic equipment - Google Patents

Abstract

A slew rate control apparatus includes voltage detecting means, charging and discharging means, and control means. The voltage detecting means detects a first voltage and a second voltage on both ends of at least one switch. The charging and discharging means outputs a current for charging at least one of the both ends of the switch and for inputting a current for discharging the at least one end. The control means controls a slew rate by turning on the switch when the first voltage detected by the voltage detecting means has reached the second voltage, and outputs a current for charging at least one of two terminals on the both ends of the switch or discharging the at least one terminal according to a magnitude relationship between the first voltage and the second voltage when the first voltage does not reached the second voltage.

Description

Slewing rate control device, semiconductor device and electronic device

The present invention relates to a slew rate control device that controls a slew rate when switching a power source voltage, a semiconductor device including the slew rate control device, and an electronic device including the slew rate control device.

Today, USB (Universal Serial Bus) is widely used in the field of electronic devices such as personal computers, mobile phones, smart phones, and the like. In this USB, the new specification USB Power Delivery (USBPD), which is used to supply power from the conventional 5V/1.5A to the maximum of 20V/5A, is being developed by each company.

Compared with the USB specification of the prior art, in order to correspond to a plurality of supply voltages (5V/12V/20V, etc.) in the USBPD specification, it is necessary to have a plurality of power sources so as to be able to supply an appropriate voltage to the connected devices when the cable is connected. Communication, by switching the switch IC or field effect transistor (FET) to the required power supply to achieve USBPD function, such technology is known and is known.

As a feature of the USBPD specification, that is, as a method of switching the supply voltage, it is required to slowly switch the supply voltage in order to prevent malfunction of the connected device and prevent unnecessary electromagnetic field radiation. Here, specifically, it is required to raise and lower the voltage at a predetermined slew rate when the power source voltage is switched. The slew rate is the amount of voltage change per unit time, and V/s is used as a unit.

[Previous Technical Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2005-275611.

However, in order to slowly switch the supply voltage, for example, it is necessary to increase the capacitance of the output terminal such as the VBUS node or to increase the resistance and/or the capacitance of the switch control terminal, and then it is necessary to adjust the respective power sources using the component value.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a slew rate control apparatus capable of controlling a slew rate with a simple circuit as compared with the prior art when switching a supply voltage.

A slew rate control device according to an aspect of the present invention includes a voltage detecting means, a charging and discharging means, and a control means. The voltage detecting means detects the first voltage and the second voltage of the two ends of the at least one switch. The charging and discharging means outputs a current for charging to at least one of both ends of the switch, or inputs a current for discharging from the at least one end. Controlling means that when the first voltage detected by the voltage detecting means reaches the second voltage, the switch is turned on, and when the first voltage does not reach the second voltage, corresponding to the first voltage and the second voltage In relation to the size, at least one of the two terminals of the switch has a current for charging or is discharged from the at least one terminal, thereby controlling the slew rate.

Therefore, according to the slew rate control apparatus of the present invention, the slew rate can be controlled with a simple circuit without increasing the number of adjustment elements when switching the supply voltage as compared with the prior art.

1‧‧‧Power supply

1-1~1-N‧‧‧Power supply

2‧‧‧Load circuit

3‧‧‧ switch

3-1~3-N‧‧‧ switch

3a‧‧‧Contact terminals

3a-1~3a-N‧‧‧Contact Terminal

3b‧‧‧Contact terminals

3b-1~3b-N‧‧‧Contact Terminal

10‧‧‧Slewing rate control device

10A‧‧‧swing rate control device

10B‧‧‧swing rate control device

10C‧‧‧swing rate control device

20‧‧‧Control circuit

20A‧‧‧Control circuit

20B‧‧‧Control circuit

20C‧‧‧Control circuit

20m‧‧‧ memory

21‧‧‧Voltage detection circuit

21B‧‧‧Voltage detection circuit

22‧‧‧ slew rate adjustment circuit

22B‧‧‧ slew rate adjustment circuit

22C‧‧‧swing rate adjustment circuit

23‧‧‧Switch drive circuit

23B‧‧‧Switch drive circuit

30‧‧‧Automatic adjustment device for slew rate

31‧‧‧ slew rate calculation circuit

32‧‧‧Error signal generation circuit

33‧‧‧ Swing rate adjustment control signal generation circuit (SR adjustment control signal generation circuit)

41‧‧‧Delay circuit

42‧‧‧Adder

43‧‧‧Signal adjustment circuit

44‧‧‧Adder

45‧‧‧Signal adjustment circuit

51‧‧‧current source

52‧‧‧current source

53‧‧‧current source

54‧‧‧current source

90‧‧‧Charging/discharging circuit

91‧‧‧current source

92‧‧‧current source

CL‧‧‧ load capacitance

IC‧‧‧Charging current

Icharge‧‧‧Charging current

Idischarge‧‧‧discharge current

IL‧‧‧Charging current

RL‧‧‧ load resistor

S1~S8‧‧‧Steps

S1A‧‧‧ steps

S11~S17‧‧‧Steps

S21~S24‧‧‧Steps

SRerror‧‧‧ error

T0~t3‧‧‧Time

V1‧‧‧Power supply voltage

V1-1~V1-N‧‧‧Power supply voltage

V2‧‧‧ load terminal voltage

VDD‧‧‧Power supply voltage

VR‧‧‧Variable resistor

Fig. 1A is a block diagram showing an example of the configuration of a rotation rate control device 10 and its peripheral circuits according to the first embodiment of the present invention.

Fig. 1B is a block diagram showing a configuration example of a rotation speed control device 10A and its peripheral circuits according to a first modification of the first embodiment of the present invention.

Fig. 2A is a flowchart showing a slew rate control process (when voltages V1 and V2 are unknown) are performed by the slew rate control device 10 of Fig. 1A.

Fig. 2B is a flowchart showing the slew rate control processing (when the voltage V1 is known to be unknown V2) by the slew rate control device 10 of Fig. 1A.

Fig. 2C is a flowchart showing a second embodiment of the first modification in which the slew rate control device 10 of Fig. 1A executes the slew rate control processing (when the voltages V1 and V2 are unknown).

Fig. 2D is a flowchart showing a second embodiment of the first embodiment in which the slew rate control device 10 of Fig. 1A executes the slew rate control processing (when the voltage V1 is known to be unknown V2).

Fig. 2E is a flowchart showing a third embodiment of the first embodiment in which the slew rate control device 10 of Fig. 1A executes the slew rate control processing (when the voltages V1 and V2 are unknown).

Fig. 2F is a flowchart showing a fourth modification of the first embodiment in which the slew rate control device 10 of Fig. 1A executes the slew rate control processing (when the voltage V1 is known to be unknown V2).

FIG. 3 is a circuit diagram showing a configuration example of the rotation rate adjustment circuit 22 of FIG. 1A.

Fig. 4 is a timing chart showing an operation example of the rotation rate control device 10 of Fig. 1A.

Fig. 5 is a block diagram showing an example of the configuration of the rotation rate control device 10B and its peripheral circuits according to the second embodiment of the present invention.

Fig. 6 is a block diagram showing an example of the configuration of a rotation rate control device 10C and its peripheral circuits according to the third embodiment of the present invention.

Fig. 7A is a flowchart showing a slew rate control process (when voltages V1 and V2 are unknown) are executed by the slew rate control device 10C of Fig. 6 .

Fig. 7B is a flowchart showing the slew rate control processing (when the voltage V1 is known to be unknown V2) by the slew rate control device 10C of Fig. 6 .

Fig. 8 is a flowchart showing the subroutine of Figs. 7A and 7B, that is, the slew rate automatic adjustment processing (S7, S8).

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same components are denoted by the same reference numerals.

[Embodiment 1]

Fig. 1A is a block diagram showing an example of the configuration of a rotation rate control device 10 and its peripheral circuits according to the first embodiment of the present invention. The slew rate control device 10 of FIG. 1A has the following features: including a switch control device, detecting The voltages V1, V2 of the contact terminals 3a, 3b at both ends of the switch 3 inserted between the power source 1 and the load circuit 2 are controlled, and the slew rate of the voltage V2 supplied to the load circuit 2 is controlled. Here, the switch 3 is, for example, a single-pole single-shot switch, the voltage V1 is referred to as a power supply voltage V1, and the voltage V2 is referred to as a load terminal voltage V2. The slew rate control device 10 is configured to include a control circuit 20, a voltage detecting circuit 21, a slew rate adjusting circuit 22, and a switch driving circuit 23. Further, the load circuit 2 is, for example, a parallel circuit of the load resistor RL and the load capacitor CL.

In particular, the swing rate control device 10 has the following feature when switching the supply voltage to the load circuit 2 in, for example, the USB PD by performing the slew rate control process of FIG. 2A or FIG. 2B: the slew rate control device 10 detects the power supply voltage V1. The on/off control of the switch 3 is performed in response to the detected voltage with the load voltage V2, and the load circuit 2 is charged or discharged by the slew rate adjustment circuit 22, thereby controlling the slew rate at the time of switching of the supply voltage.

First, the configuration of the swing rate control device 10 will be described below.

The slew rate adjustment circuit 22 is connected in parallel with the contact terminals 3a, 3b of the switch 3, and has a current output circuit corresponding to the control signal from the control circuit 20 for charging or discharging the load capacitance CL. The voltage detecting circuit 21 detects the voltages V1, V2 at both ends of the switch 3, and outputs a signal indicating the detected voltages V1, V2 to the control circuit 20. The switch drive circuit 23 generates a drive control signal required for ON/OFF of the switch 3 based on the ON/OFF signal from the switch 3 of the control circuit 20, and outputs it to the switch 3. The control circuit 20 controls the operation of the slew rate adjusting circuit 22 based on the information of the voltages V1, V2 at both ends of the switch 3 detected by the voltage detecting circuit 21, and simultaneously generates an on/off driving control signal for the switch driving circuit 23.

Fig. 2A is a flow chart showing the slew rate control process (when voltages V1 and V2 are unknown) by the control circuit 20 of the slew rate control device 10 of Fig. 1A. At the start of the process of Fig. 2A, the switch 3 is in the closed state, and the same applies to the slew rate control process which will be described later.

In step S1 of FIG. 2A, the voltage detecting circuit 21 detects the load terminal voltage V2 and the power source voltage V1, and determines whether or not |V1 - V2 | ≦ ΔV in step S2. Here, ΔV is a value smaller than the voltages V1 and V2, and is, for example, 20 V ± 5%, and is set to a size of 0.1 V to 1 V in the present embodiment. This judgment determines whether the load terminal voltage V2 substantially reaches the power supply voltage V1. YES (YES) proceeds to step S3, whereas NO (NO) proceeds to step S4. In step S3, the switch drive circuit 23 turns on the switch 3 and ends the slew rate control process. On the other hand, in step S4, it is judged whether or not V2 < V1, and if YES (YES), the process proceeds to step S5, whereas if NO (NO), the process proceeds to step S6. The slew rate adjustment circuit 22 pairs the load circuit 2 in step S5 Charging and returning to step S1, the control processing is periodically repeated at a predetermined cycle. Further, in step S6, the slew rate adjustment circuit 22 discharges from the load circuit 2 and returns to step S1 to periodically repeat the control process at a predetermined cycle.

Fig. 2B is a flow chart showing the slew rate control process (when the voltage V1 is known to be unknown V2) by the slew rate control device 10 of Fig. 1A. The slew rate control process of Fig. 2B is characterized in that step S1 is replaced with step S1 instead of step S1 as compared with the slew rate control process of Fig. 2A, and the other processes are the same. In step S1A, the voltage detecting circuit 21 detects only the load terminal voltage V2. Therefore, the voltage detecting circuit 21 has a unique effect of detecting only one load terminal voltage V2.

In the swing rate control device 10 configured as described above, in the rated state in which the charging of the load capacitance CL is completed, the load terminal voltage V2 is expressed by the following equation with respect to the charging current IL flowing through the load resistor RL.

V2=IL×RL (1)

In order to rise to the power supply voltage V1, the load terminal voltage V2 may be such that the current value IL>V1/RL of the connected power supply voltage V1 is obtained. Therefore, if the charging current IC is IC>V1/RL, the load capacitance CL can be charged to the power supply voltage V1. That is, if the slew rate of the load terminal voltage V2 is such that the charging current IC is greater than the current flowing through the load resistor RL, since the load capacitance CL can be charged to the power supply voltage V1, the charging current of the slew rate adjusting circuit 22 can be adjusted. Value to control.

Fig. 1B is a block diagram showing a configuration example of a rotation speed control device 10A and its peripheral circuits according to a first modification of the first embodiment of the present invention. When the load resistor RL is relatively small and the current flowing is large, the resistor structure that becomes the load at the connection end of the switch 3, for example, a communication device such as an IC (integrated circuit), the control circuit 20A performs communication at the time of charging. At this time, the load resistor RL is the variable resistor VR, and when the resistor can be adjusted, the current adjustment that flows may be reduced as shown in FIG. 1B.

Fig. 2C is a flowchart showing a second embodiment of the first modification in which the slew rate control device 10 of Fig. 1A executes the slew rate control processing (when the voltages V1 and V2 are unknown). 2D is a flowchart showing the second embodiment of the first embodiment in which the slew rate control device 10 of FIG. 1A performs the slew rate control processing (when the voltage V1 is known to be unknown V2). When the charge and discharge current is fixed, the charge current IL flowing through the load resistor RL is sufficiently smaller than the charge current Icharge or the discharge current Idischarge, the slew rate becomes almost constant, and the load terminal voltage V2 is proportional to time. In this case, step S21 of FIG. 2C and FIG. 2D may be used at the beginning of charging or discharging. After the waiting time is set, the load terminal voltage V2 and the power supply voltage V1 are not required to be measured several times, and the switch 3 is controlled to be turned on after the waiting time. This waiting time can be obtained and set in the following manner.

When the load terminal voltage at time t is V(t), the charge/discharge current is I, the load capacitance is C, and the initial voltage is Vinit, it is expressed by the following equation.

V(t)=t×I/C+Vinit (2)

Thus, the time t when the load terminal voltage V(t) becomes equal to the power supply voltage Vdd is the waiting time twait. By substituting V(twait)=Vdd into equation (2), the waiting time twait can be obtained from the following equation.

Twait=(Vdd-Vinit)×C/I (3)

Here, the set value of the waiting time may be a fixed value, or may be controlled from the system and read from the memory device.

Fig. 2E is a flowchart showing a third embodiment of the first embodiment in which the slew rate control device 10 of Fig. 1A executes the slew rate control processing (when the voltages V1 and V2 are unknown). 2F is a flowchart showing a fourth embodiment of the first embodiment in which the slew rate control device 10 of FIG. 1A executes the slew rate control processing (when the voltage V1 is known to be unknown V2). When the charging current IL flowing through the load resistor RL becomes larger than the charging current Icharge or the discharging current Idischarge, the slew rate control can only perform an intermediate process to the load terminal voltage V2. Therefore, in this case, the opening switch 3 can be forcibly controlled after a certain time as shown in steps S22 to S24 of FIGS. 2E and 2F.

FIG. 3 is a circuit diagram showing a configuration example of the rotation rate adjustment circuit 22 of FIG. 1A. In FIG. 3, the slew rate adjustment circuit 22 is configured to have: (1) a current source 51 for charging a charging circuit connected to the load circuit 2 of the contact terminal 3b, and connected to the power supply voltage VDD and connected Between the point terminals 3b; (2) a current source 52 for discharging a circuit from the load circuit 2 connected to the contact terminal 3b, and connected between the ground terminal and the contact terminal 3b; (3) a current source 53, which is a charging circuit for charging a power source 1 (for example, a rechargeable battery) connected to the contact terminal 3a, and is connected between the power source voltage VDD and the contact terminal 3a; (4) a current source 54, It is used for discharging a discharge circuit from a power source 1 (for example, a rechargeable battery) connected to the contact terminal 3a, and is connected between the ground terminal and the contact terminal 3a; and (5) a charging/discharging circuit 90, connected Between the contact terminal 3a and the contact terminal 3b.

Here, the charging/discharging circuit 90 is configured to have: (1) a current source 91 for charging a load circuit 2 connected to the contact terminal 3b or a charging/discharging circuit for discharging from a power source 1 (for example, a rechargeable battery) connected to the contact terminal 3a, and Connected between the contact terminal 3a and the contact terminal 3b; and (2) a current source 92 for charging the power source 1 (e.g., a rechargeable battery) connected to the contact terminal 3a, or from the connection to the contact The charging/discharging circuit for discharging the load circuit 2 of the terminal 3b is connected between the contact terminal 3a and the contact terminal 3b.

The on/off and current quantities of the current sources 51-54, 91, 92 of FIG. 3 are controlled by control signals from the control circuit 20. Here, the control of the current amount adjustment of charging or discharging may be directly controlled as a fixed value in the slew rate control, or may be dynamically controlled corresponding to the time, or may be corresponding to, for example, the switch displayed by the voltage detecting circuit. The voltage value of the terminal is controlled.

The rotation rate adjustment circuit 22 of FIG. 3 is configured using a plurality of current sources 51 to 54, 91, and 92. However, the present invention is not limited thereto, and each of the current sources 51 to 54, 91, and 92 may have the following configuration.

(1) Connect to the power supply voltage VDD or ground, and use a series circuit such as a switch and a variable resistor.

(2) Connect to the power supply voltage VDD or the ground terminal, and use, for example, a switched capacitor circuit composed of a plurality of switches, variable resistors, and capacitors.

Further, the amount of charge or the amount of discharge in the slew rate adjustment circuit 22 of FIG. 3 can be adjusted in the following manner instead of the current amount of the current sources 51 to 54, 91, and 92.

(1) A parallel circuit using a plurality of variable current sources.

(2) Instead of the power supply voltage VDD or ground, use a voltage regulator circuit.

(3) After the digital control signal is input to the DA converter, the output signal of the DA converter is controlled by the signal adjustment circuit or the signal conversion circuit to control the amount of charge or discharge of the charging/discharging circuit.

(4) The charge amount or the discharge amount of the charge/discharge circuit is controlled by the signal adjustment circuit or the signal conversion circuit based on the analog control signal.

Fig. 4 is a timing chart showing an operation example of the rotation rate control device 10 of Fig. 1A. Next, with reference to FIG. 4, in the slew rate control processing of FIG. 2A, a case where the control circuit corresponding to the load terminal voltage V2 and the power supply voltage V1 is unknown will supply power to the load circuit 2 in the order of time t1 to t3.

(SS1) In the time t0 to t1, the voltage detecting circuit 21 measures the load terminal voltage V2 and the power supply voltage V1, and compares the voltages to determine whether the load terminal voltage V2 reaches the power supply voltage V1. When |V1 - V2| > ΔV, the load terminal voltage V2 does not reach the power supply voltage V1. For example, when V2 < V1, the load circuit 2 is charged by the slew rate adjustment circuit 22.

(SS2) In the time t1 to t2, the processing of the step SS1 is repeated until the load terminal voltage V2 reaches the power supply voltage V1.

(SS3) At time t2, if the load terminal voltage V2 reaches the power supply voltage V1, the switch drive circuit 23 controls the open switch 3.

(SS4) During the time t2 to t3, since the switch 3 is turned on, power supply from the power source 1 to the load circuit 2 is started. Here, after the switch 3 is turned on, the action of the slew rate adjustment circuit 22 may be kept on or off.

(SS5) After the time t3, when the power supply of the load circuit 2 is completed and the charging is completed, the switch 3 is turned off. Here, the voltage held by the load capacitance CL of the load circuit 2 remains, and the charge of this voltage is discharged by the load resistor RL. Further, in the case where the discharge is slow, the discharge circuit may be discharged through the discharge circuit to the ground terminal of the slew rate adjustment circuit 22.

According to the embodiment of the present invention as described above, when the supply voltage is switched in the power supply circuit such as the USBPD, the load capacitance CL of the load circuit 2 is charged by the slew rate adjustment circuit 22 in the slew rate control device 10. Next, the slew rate is adjusted by the amount of charging current, and the switch 3 is turned on until the load terminal voltage V2 reaches the power source voltage V1. Thereby, the swing rate control device 10 can adjust the swing rate without depending on the state of the switch 3. Here, when the supply voltage is switched, the slew rate can be controlled without increasing the adjustment element. Further, as the switch 3, various types of switches as in the first to third embodiments can be used.

[Embodiment 2]

Fig. 5 is a block diagram showing an example of the configuration of the rotation rate control device 10B and its peripheral circuits according to the second embodiment of the present invention. In the second embodiment of Fig. 5, the rotation rate control device 10B differs from the rotation rate control device 10 of the first embodiment of Fig. 1A in the following points.

(1) In place of the power supply 1, it is configured as a single-pole N-turn switching circuit and has a plurality of (N) power supplies 1-1 to 1-N.

(2) Instead of the switch 3, there are a plurality of (N) switches 3-1 to 3-N.

(3) In place of the slew rate control device 10, the slew rate control device 10B is provided.

Hereinafter, the differences will be described in detail.

In FIG. 5, the contact terminal 3a-1 of the switch 3-1 is connected to the power source 1-1, and the contact terminal 3b-1 of the switch 3-1 is connected to the load circuit 2 via the contact terminal 3b. The contact terminal 3a-2 of the switch 3-2 is connected to the power source 1-2, and the contact terminal 3b-2 of the switch 3-2 is connected to the load circuit 2 via the contact terminal 3b. Following the same rule, the contact terminals 3a-N of the switch 3-N are connected to the power source 1-N, and the contact terminals 3b-N of the switch 3-N are connected to the load circuit 2 via the contact terminal 3b. Here, the power supply voltages of the power sources 1-1 to 1-N are respectively V1-1 to V1-N.

The slew rate control device 10B includes a control circuit 20B, a voltage detecting circuit 21B, a slew rate adjusting circuit 22B, and a switch driving circuit 23B in order to control the plurality of switches 3-1 to 3-N and the power sources 1-1 to 1-N.

According to the second embodiment of the present invention having the above configuration, the slew rate control can be performed with respect to the plurality of (N) power sources 1-1 to 1-N, the switches 3-1 to 3-N, and the load circuit 2. Here, the slew rate control device 10B can adjust the slew rate without depending on the state of the switches 3-1 to 3-N. Here, when the supply voltage is switched, the slew rate can be controlled without increasing the adjustment element.

[Embodiment 3]

Fig. 6 is a block diagram showing an example of the configuration of a rotation rate control device 10C and its peripheral circuits according to the third embodiment of the present invention. In the third embodiment of Fig. 6, the rotation rate control device 10C differs from the rotation rate control device 10 of the first embodiment of Fig. 1 in the following points.

(1) There is also a slew rate automatic adjusting device 30.

(2) In place of the control circuit 20, the control circuit 20C includes a memory 20m that stores a slew rate setting value (hereinafter referred to as an SR set value) in advance.

(3) In place of the slew rate adjustment circuit 22, the slew rate adjustment circuit 22C is provided.

Hereinafter, the differences will be described in detail.

In FIG. 6, the slew rate automatic adjusting device 30 is used to automatically adjust the slew rate of the load terminal voltage V2, and has a slew rate calculating circuit 31, an error signal generating circuit 32, and a slew rate adjustment control signal generating circuit 33. Here, the automatic slew rate adjusting device 30 is characterized in that the slew rate is automatically adjusted by using negative feedback so that the slew rate of the load terminal voltage V2 becomes a desired slew rate value.

The slew rate calculation circuit 31 has, for example, a delay circuit 41 and an adder 42, and calculates a slew rate from the load terminal voltage V2. Here, the delay circuit 41 delays the load terminal voltage V2 only for a predetermined time and outputs a delay signal. The adder 42 subtracts the delay signal from the signal indicating the load terminal voltage V2, and then subtracts the subtraction meter. The signal of the result is output to the error signal generating circuit 32. Therefore, the slew rate calculation circuit 31 can calculate the amount of voltage change per delay time, that is, the slew rate can be calculated.

The error signal generating circuit 32 has, for example, a signal adjusting circuit 43 composed of an amplifier or a filter, and an adder 44, and calculates an error with respect to the slew rate obtained by the slew rate calculating circuit 31 for the required SR setting value. . The slew rate calculated by the slew rate calculating circuit 31 is subjected to a predetermined signal adjustment process by the signal adjusting circuit 43. Next, the adder 44 subtracts the signal after the signal adjustment process from the signal indicating the SR set value, and outputs the error signal SRerror of the subtraction calculation result to the slew rate adjustment control signal generating circuit 33, wherein the SR set value is from the control circuit 20C. The memory is read by 20m. The calculation of the error may be calculated not only as a subtraction calculation but as a ratio (division calculation value) with respect to the required slew rate value, or may be a feedback for removing the noise and changing the loop by the signal adjustment circuit 43. The signal is adjusted by filter, amplification/attenuation processing, and averaging.

The slew rate adjustment control signal generating circuit 33 (hereinafter referred to as the SR adjustment control signal generating circuit) has a signal adjusting circuit 45 composed of, for example, an amplifier or a filter, and the SR adjusting signal control generating circuit 33 calculates based on the error signal generating circuit 32. The error signal SRerror generates a slew rate adjustment control signal (hereinafter referred to as an SR adjustment control signal) indicating a slew rate adjustment value (that is, a charge/discharge current adjustment, hereinafter referred to as an SR adjustment value). The SR adjustment control signal is input to the slew rate adjustment circuit 22C. Therefore, the SR adjustment control signal generating circuit 33 can optimize the feedback signal level to the slew rate adjustment circuit 22C by, for example, filtering or amplifying the error signal in a manner that the feedback signal level is optimized with respect to the slew rate adjustment circuit 22C. Control signal optimization.

Further, the slew rate adjustment circuit 22C adjusts the slew rate such that the slew rate becomes the SR adjustment value based on the control signal from the SR adjustment control signal and the control circuit 20C.

The control circuit 20C of FIG. 6 has the memory 20m for storing the SR set value, but the present invention is not limited thereto, and may be configured to receive the SR set value from an external control circuit or control device.

The signal processing in the slew rate adjusting device 30 can be performed in an environment of either analog or digital or both. If the analog signal processing is performed, the sampling and holding circuit, the switched capacitor circuit, the operational amplifier, etc. are used. Features. Moreover, if it is a digital signal processing, the input signal is AD-converted, and the processing in the subsequent stages is all performed by digital signal processing. That is to say, the processing of the function can be realized regardless of the distinction of the analog/digital signal processing. In the case of digital signal processing In the case where the input signal to the slew rate automatic adjusting device 30 is subjected to AD conversion processing, the voltage detecting circuit 21 may be shared with the voltage detecting circuit 21 if the AD converter is used.

Fig. 7A is a flowchart showing a slew rate control process (when voltages V1 and V2 are unknown) are executed by the slew rate control device 10C of Fig. 6 . The slew rate control processing of FIG. 7A is compared with the slew rate control processing of FIG. 2A, and is characterized in that the slew rate automatic adjustment processing of FIG. 8 is executed in each of the subsequent steps S7, S8 of steps S5, S6.

Further, Fig. 7B is a flowchart showing the slew rate control processing (when the voltage V1 is known to be unknown V2) by the slew rate control device 10C of Fig. 6 . The slew rate control processing of FIG. 7B is compared with the slew rate control processing of FIG. 2B, and is characterized in that the slew rate automatic adjustment processing of FIG. 8 is executed in each of the subsequent steps S7, S8 of steps S5, S6.

Fig. 8 is a flowchart showing the subroutine of Figs. 7A and 7B, that is, the slew rate automatic adjustment processing (S7, S8).

In step S11 of Fig. 8, the voltage detecting circuit 21 measures the load terminal voltage V2, and then, in step S12, the slew rate is calculated based on the measured load terminal voltage V2. In step S13, the error SRerror is calculated based on the calculated slew rate and the slew rate setting value, and it is determined in step S14 whether or not SRerror ≦ ΔSR, YES (YES) returns to the original flow, and NO (NO) proceeds to step S15. Here, ΔSR is, for example, a nearby value of 0 such as 0.01 to 0.1. It is determined in step S15 whether SRerror > 0, YES (YES) proceeds to step S16, and if NO (NO), proceeds to step S17. The adjustment value x of the swing rate adjustment circuit 22 is reduced based on the error SRerror in step S16, and is updated to return to the original flow. Further, in step S17, the adjustment value x of the rotation rate adjustment circuit 22 is amplified based on the error SRerror, and is updated and returned to the original flow.

In step S14 of FIG. 8, if the error SRerror becomes within the vicinity of 0, and the adjustment value of the rotation rate adjustment circuit 22C is regarded as the optimum value with respect to the required rotation rate, the adjustment value is not updated and the operation returns to The original process. Further, the comparison processing in the vicinity of the value of whether the error SRerror is 0 or not may be performed, and the adjustment value of the rotation rate adjustment circuit 22C may be increased and decreased at any time.

As described above, with respect to the slew rate control processing of FIGS. 2A and 2B, the slew rate automatic adjustment processing can be realized by increasing the subroutine of the slew rate automatic adjustment processing. This subroutine can be realized by sequentially adjusting the current value of charging/discharging in accordance with the flowchart of FIG. Further, the third embodiment can be applied not only to the first embodiment but also to the second embodiment.

[Modification]

The rotation rate control device according to the first to third embodiments described above can be provided in a semiconductor device such as a semiconductor integrated circuit.

Further, the slew rate control devices of the above-described first to third embodiments can be installed in electronic devices such as personal computers, mobile phones, and smart phones.

1‧‧‧Power supply

2‧‧‧Load circuit

3‧‧‧ switch

3a‧‧‧Contact terminals

3b‧‧‧Contact terminals

10‧‧‧Slewing rate control device

20‧‧‧Control circuit

21‧‧‧Voltage detection circuit

22‧‧‧ slew rate adjustment circuit

23‧‧‧Switch drive circuit

CL‧‧‧ load capacitance

RL‧‧‧ load resistor

V1‧‧‧Power supply voltage

V2‧‧‧ load terminal voltage

Claims (9)

A slew rate control device includes: a voltage detecting means for detecting a first voltage and a second voltage of the two ends of the at least one switch; and a charging and discharging means for outputting a current for charging at least one of the two ends of the switch, or from the current And at least one end inputs a current for discharging; and a control means, when the first voltage detected by the voltage detecting means reaches the second voltage, turning on the switch, and when the first voltage does not reach the second voltage, Corresponding to the magnitude relationship between the first voltage and the second voltage, at least one of the two terminals of the switch has a current for charging or is discharged from the at least one terminal, thereby controlling the slew rate. A slew rate control device comprising: a voltage detecting means for detecting a first voltage of one end of at least one of the switches; and a charging and discharging means for outputting a current for charging at least one of the two ends of the switch, or from the at least One end inputs a current for discharging; and a control means that when the first voltage detected by the voltage detecting means reaches a predetermined second voltage, the switch is turned on, and when the first voltage does not reach the second voltage, Corresponding to the magnitude relationship between the first voltage and the second voltage, at least one of the two terminals of the switch has a current for charging or is discharged from the at least one terminal, thereby controlling the slew rate. The yaw rate control device according to claim 1 or 2, wherein the load circuit connecting one end of the switch includes a variable resistor, and the control means controls the variable resistor during the charging or discharging The resistance value. The yaw rate control device according to any one of claims 1 to 3, further comprising: calculating means for calculating, when the charging/discharging means charges at least one of both ends of the switch or when discharging a slew rate; and a signal generating means for generating an error signal indicating an error between the calculated slew rate and a predetermined slew rate setting value; wherein the control means automatically controls the calculated slew rate and the swivel based on the error signal The rate setting values are the same. The yaw rate control device according to any one of claims 1 to 4, wherein the first voltage is a load terminal voltage and the second voltage is a power source voltage. The yaw rate control device according to any one of claims 1 to 5, wherein the control means is controlled in such a manner that at least one of the two terminals of the switch is output for charging The current; or after discharging from the at least one terminal, the switch is turned on after a predetermined waiting time. The yaw rate control device according to any one of claims 1 to 5, wherein the control means is controlled in such a manner that at least one of the two terminals of the switch is output for charging The current is turned on; or after discharging from the at least one terminal, when the current for charging or discharging becomes larger than a predetermined current value, the switch is turned on after a predetermined waiting time. A semiconductor device comprising the slew rate control device according to any one of claims 1 to 7. An electronic device comprising the slew rate control device according to any one of claims 1 to 7.