JP2012175789A - Control semiconductor device for switching power supply - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated circuit having a function capable of setting its parameters through or not through serial communication without increasing the number of terminals.SOLUTION: The integrated circuit includes: a data input terminal DA for receiving data from outside; a clock terminal CK for receiving a clock signal; address terminals A0, A1a; a serial interface circuit 11 which converts the signal input to the data input terminal DA into a signal to an internal circuit; and a clock detection circuit 14 which detects the input of the clock signal. Parameters can be set with the existent terminals without data communication from a microcomputer by switching part of or the whole of data of output of the serial interface circuit 11 to data based upon terminal states of the data input terminal DA and address terminals A0, A1 and processing the data until the clock detection circuit 14 detects a predetermined clock signal.

Description

  The present invention relates to an integrated circuit that reads necessary data by communication, particularly serial communication.

  In recent years, with the development of digital technology, an IC (semiconductor integrated circuit; hereinafter simply referred to as an integrated circuit) that sets its own parameters in response to a command from a central control circuit (hereinafter simply referred to as a microcomputer) composed of a microcomputer or the like. ) Is increasing. One example is a power management system that comprehensively supplies a plurality of power supplies. As shown in FIG. 4, the power management system includes a microcomputer 100 and power supply control ICs 210, 220, 230,. The power supply control ICs 210, 220, 230,... Belong to each of the plurality of power supplies (hereinafter, each power supply is also referred to as a channel). Each channel is controlled such as determining the start-up timing (see, for example, Patent Documents 1 to 3). Communication from the microcomputer to the power supply control IC is often performed by serial communication that can be configured with a small number of signal lines. FIG. 4 shows a system for transmitting serial data output from the data terminal DA to the power supply control ICs 210, 220, 230,... While determining the timing with the clock signal output from the clock terminal CK of the microcomputer.

  FIG. 5 shows a configuration example of a power supply control IC used in a conventional power management system. The power supply control IC 200 feeds back the output voltage to the clock terminal CK, the data input terminal DA, the address terminals A0 and A1, the output terminals OUT1 and OUT2 for outputting signals for driving the external switching elements M1 and M2. FB terminal, a serial interface circuit 201 for performing serial communication, a register 202 for storing setting values for determining various parameters based on communication results, and a setting value stored (written) in the register 202 And a control circuit 203 for controlling the channel. Address terminals A0 and A1 are terminals for identifying individual power supply control ICs when a plurality of similar power supply control ICs are commonly connected to a serial data bus from the microcomputer to communicate with the microcomputer. The serial interface circuit 201 has a serial / parallel conversion function, and is a circuit that controls the generation of the parameters and the writing to the register 202.

  Outside the power supply control IC 200, there are a switching element composed of N-channel MOS transistors M 1 and M 2 that receive signals output from the OUT 1 terminal and OUT 2 terminal at their gates, and an inductor L connected to the connection point of the switching elements M 1 and M 2, respectively. A smoothing filter made of a capacitor Co is connected to form a switching power supply circuit. Switching elements M1 and M2 are alternately turned on and off under the control of a signal from power supply control IC 200, and the potential at the connection point of switching elements M1 and M2 is smoothed by a smoothing filter to become output voltage Vo. The output voltage Vo is fed back to the power supply control IC 200, and the power supply control IC 200 controls on / off of the switching elements M1, M2 so that the output voltage Vo becomes a predetermined value based on the feedback signal.

  Here, power supply control IC 200 is shown as an example in which power supply start / stop, switching frequency and output voltage are set by serial communication, but the present invention and embodiments of the invention described later are also limited to this. is not. The power supply control IC 200 is provided with a power-on reset circuit or a reset terminal (not shown), and the power supply control IC 200 is reset when the power supply control IC 200 rises. The register 202 of the power supply control IC 200 immediately after the reset is released is in an initial state in which the power supply is stopped and the switching frequency and the output voltage are initially set. Thereafter, the microcomputer designates the power supply control IC 200 by address input to the address terminals A0 and A1, and transmits data to the data input terminal DA in synchronization with the clock signal to the clock terminal CK. The channel can be operated at a desired output voltage and switching frequency by instructing the activation of the power supply after writing the set value (parameter) indicating the frequency in the register 202.

JP 2005-327241 A JP 2005-328405 A JP 2006-67559 A

  In a system using a microcomputer, data transfer by serial communication is easy. However, it is not easy to realize serial communication in a system that does not perform centralized control by a microcomputer. It is not realistic to use the same power supply control IC in a system that uses a microcomputer and a system that does not use a microcomputer, and to provide a serial communication circuit for setting each channel in a system that does not use a microcomputer.

  On the other hand, if a single IC can handle various applications, it is a great advantage of reducing the types of parts used. If a function that can set the power supply start / stop, switching frequency, and output voltage is simply added to the conventional power supply control IC in addition to the setting by serial communication, it will be necessary to provide a dedicated terminal for that purpose. There is a problem that it leads to an increase in area.

  The present invention solves the above-mentioned problems related to the prior art, and provides an integrated circuit having a function capable of setting its own parameter by serial communication without causing an increase in terminals and setting it independently. With the goal.

  In order to solve the above problem, the invention according to claim 1 includes a data input terminal for inputting data from the outside, and a clock terminal for inputting a clock signal for controlling the input timing of the data. One or a plurality of address terminals, a conversion circuit that converts a signal input to the data input terminal into a signal to an internal circuit, and a clock detection circuit that detects that the clock signal is input. Until the clock detection circuit detects the clock signal, a part or all of the output of the conversion circuit is converted to data based on the terminal states of the data input terminal and the address terminal. It is an integrated circuit that processes by switching.

  The invention according to claim 2 is the invention according to claim 1, wherein a part or all of the output of the conversion circuit and a part or all of the data input to the data input terminal and the address terminal are It has a switching circuit which switches according to the output of the clock detection circuit.

  According to a third aspect of the present invention, in the first aspect of the invention, a part of the output of the conversion circuit is a signal for setting a parameter relating to the operation of the integrated circuit, and the clock detection circuit detects the clock signal. Up to this point, the parameter is set by data based on the terminal state of part or all of the data input terminal and the address terminal.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the parameter that is set until the clock detection circuit detects the clock signal includes a part or all of the data input terminal and the address terminal. It is set based on the resistance value or the capacitance value of the resistor connected to the capacitor or the capacitor.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the data is serial data, and the conversion circuit has a serial-parallel conversion function.

  The integrated circuit of the present invention includes a data input terminal for inputting data from the outside, a clock terminal for inputting a clock signal for controlling the input timing of the data, one or a plurality of address terminals, A conversion circuit that converts a signal input to a data input terminal into a signal to an internal circuit; and a clock detection circuit that detects that the clock signal has been input. The clock detection circuit converts the clock signal Until detection, data from the microcomputer is processed by switching part or all of the output of the conversion circuit to data based on part or all of the terminal states of the data input terminal and the address terminal. Even if there is no communication, the parameters can be set with the existing terminals.

It is a figure which shows the structural example of the integrated circuit which concerns on this invention, and the switching power supply circuit using the said integrated circuit. It is a figure which shows the example of a structure of another integrated circuit based on this invention, and the switching power supply circuit using the said integrated circuit. It is a figure which shows the structural example of a setting selection circuit. It is a figure for demonstrating the structure of a power management system. It is a figure which shows the structural example of the conventional power supply control IC used for a power management system.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a configuration example of an integrated circuit 10 and a switching power supply circuit using the integrated circuit 10 according to the present invention. The same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof is omitted.
The power supply control IC 10 includes a clock terminal CK, a data input terminal DA to which serial data is input from the outside, address terminals A0 and A1, and output terminals OUT1 and OUT2 that output signals for driving the external switching elements M1 and M2. An FB terminal for feeding back the output voltage Vo, a serial interface circuit (conversion circuit) 11 for performing serial communication, a register 12 for storing various setting values for determining parameters of the integrated circuit 10, and a register 12 Of the serial interface circuit 11 according to the output of the clock detection circuit, the clock detection circuit 14 for detecting that the clock signal is input to the clock terminal CK, and the control circuit 13 for controlling the channel according to the set value stored in Part of output or data input terminal DA and address It has a switching circuit 15 for inputting a signal from the child A0, A1 to the register 12. The serial interface circuit 11 has a serial / parallel conversion function, and is a circuit that controls the generation of the parameters and the writing to the register 12. Further, the power supply control IC 10 is provided with a power-on reset circuit or a reset terminal (not shown), and the power supply control IC 10 is reset when the power supply control IC 10 rises.

  The switching circuit 15 selects and inputs signals from the data input terminal DA and the address terminals A0 and A1 to the register 12 at the time of reset. A predetermined initial value is set in the remaining portion of the register 12 to which no signal is input from the switching circuit 15. Thereafter, when predetermined data is input to the clock terminal and the data input terminal DA, the contents of the register 12 are rewritten. That is, when necessary and sufficient data to be written to the register 12 is input to the serial interface circuit 11, the clock detection circuit 14 instructs the switching circuit 15 to select the output of the serial interface circuit 11 and input it to the register 12. . The clock detection circuit 14 determines that necessary and sufficient data has been input to the serial interface circuit 11 by counting the number of pulses of the input clock signal. The register 12 reads (part of) the output signal of the serial interface circuit 11 and the output signal of the switching circuit 15. Note that the content of the register 12 remains set at the time of reset until necessary and sufficient data is input to the serial interface circuit 11, that is, until the clock detection circuit 14 finishes counting a predetermined number of pulses.

  When the power control IC 10 is connected to a microcomputer in the same way as in FIG. 4 to configure a power management system, the initial setting is performed by the first reset, and the parameters of the integrated circuit can be changed by subsequent serial communication. it can. When the power supply control IC 10 does not (cannot) perform serial communication, the data input terminal DA and the address terminals A0 and A1 may be handled as parameter setting terminals instead of communication terminals. For example, the data input terminal DA is a terminal for inputting a signal for starting / stopping, the address terminal A0 is a terminal for setting a switching frequency (selecting one of two switching frequencies), and the address terminal A1 is for setting an output voltage. Terminal (selecting one of the two output voltages).

  As described above, the power supply control IC 10 allows the data input terminal DA and the address terminals A0 and A1 to have two functions of data communication and parameter setting, so that the parameter by communication from the microcomputer is not increased without increasing the number of terminals. It is possible to achieve both setting and parameter setting not based on communication from the microcomputer.

FIG. 2 shows a configuration example of another integrated circuit 20 according to the present invention and a switching power supply circuit using the integrated circuit 20. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.
The power supply control IC 20 of FIG. 2 is provided with a setting selection circuit 16 instead of the register 12 with respect to the power supply control IC 10 of FIG. The difference is that the output is input to the setting selection circuit 16. When serial communication is not performed, resistors R0 and R1 are externally attached to address terminals A0 and A1, respectively. FIG. 2 is a diagram in which resistors R0 and R1 are externally attached to address terminals A0 and A1, respectively, in order to explain a case where serial communication is not performed.

  The power supply control IC 20 is provided with a power-on reset circuit or a reset terminal (not shown), and the power supply control IC 20 is reset when the power supply control IC 20 rises.

  The setting selection circuit 16 sets operation parameters of the circuit based on signals from the data input terminal DA and the address terminals A0 and A1 at the time of reset. The data input terminal DA is a terminal for inputting a signal for starting / stopping, the address terminal A0 is a terminal for setting a switching frequency (selecting one of two switching frequencies), and the address terminal A1 is for setting an output voltage ( The setting selection circuit 16 determines the switching frequency based on the resistance value of the resistor R0, and determines the output voltage based on the resistance value of the resistor R1. The register 17 is initially set to a predetermined value at the time of reset, and the setting selection circuit 16 sets the remaining operation parameters based on the initial setting data of the register.

  When serial communication is performed, as in the case of the power supply control IC 10 described above, when necessary and sufficient data to be written to the register 17 is input to the serial interface circuit 11, the data is transferred from the serial interface circuit 11 to the register 17. After being written, the clock detection circuit 14 instructs the setting selection circuit 16 to invalidate the operation parameters initially set by the data input terminal DA and the address terminals A0 and A1, and to reset them based on the output of the register 17.

In the power supply control IC 20, since the switching frequency and the output voltage are determined based on the resistors R0 and R1 at the time of initial setting, various settings are possible instead of two steps.
FIG. 3 shows a configuration example of the setting selection circuit 16. In FIG. 3, P-channel MOS transistors MP1 and MP2 constitute a current mirror circuit. The drain of the N-channel MOS transistor MN1 is connected to the drain of the P-channel MOS transistor MP1 serving as the input terminal of the current mirror circuit. In addition, the drain of the P-channel MOS transistor MP2 serving as the output terminal of the current mirror circuit is connected to the functional circuit 21. The gate and drain of the N-channel MOS transistor MN1 are connected to the output terminal and the inverting input terminal of the operational amplifier circuit OP1, respectively. A constant voltage Vref is input to the non-inverting input terminal of the operational amplifier circuit OP1. The terminal 22 is an address terminal A0 or A1, and is connected to a resistor Rx. The switch SW switches the connection so as to connect the resistor Rx or Rv to the drain of the N-channel MOS transistor MN1 according to the output of the clock detection circuit 14. The resistor Rv is a variable resistor and switches its resistance value according to the set value of the register 17.

  The clock detection circuit 14 connects the resistor Rx to the drain of the N-channel MOS transistor MN1 in the initial state, and then connects the variable resistor Rv to the N-channel MOS transistor MN1 when a predetermined clock signal is detected. The resistance value of the resistor Rv at that time is a value written in the register 17, that is, a value specified by an external serial signal.

  Since the two input terminals of the operational amplifier circuit OP1 are virtually short-circuited, the constant voltage Vref is applied to the resistor Rx or Rv, and the resistance value of the resistor Rx or Rv is applied to the current mirror circuit composed of the P-channel MOS transistors MP1 and MP2. The current determined by The functional circuit 21 is a current control oscillator, a current-voltage conversion circuit, or the like, and parameters such as a switching frequency and an output voltage can be set by the functional circuit 21 or another circuit to which the output is input. With this configuration, the parameter can be initially set based on the resistance connected to the address terminals A0 and A1, and then the parameter can be reset by performing serial communication.

  Although an example in which a resistor is connected to the address terminals A0 and A1 has been shown, a capacitor is connected instead of a resistor, for example, the capacitor is charged with a constant current, and the charging voltage of the capacitor becomes a predetermined voltage. The parameter may be set based on the capacity value, for example, a parameter is determined according to the time required to reach the parameter.

  Further, the data input terminal DA may be a terminal for setting another parameter instead of a signal for instructing start / stop, and a resistor or a capacitor may be connected to the data input terminal DA so that the parameter can be changed in various ways.

Although communication between the power supply control IC and the microcomputer has been described as serial communication, the present invention is not limited to this, and parallel communication may be used.
Further, although two address terminals A0 and A1 are exemplified, the present invention is not limited to this. There may be one or three or more. As the number of address terminals increases, the number of parameters that can be initialized increases. In one case, for example, a parameter of a function that is most likely to be changed, such as an output voltage, may be set at the terminal.

Also, it is not necessary to use all of the plurality of address terminals for parameter initial setting. If it is not necessary to use all the terminals, only a part of the address terminals may be used for parameter setting.
Further, the present invention realizes setting of parameters without increasing the number of terminals and without using serial communication in an integrated circuit performing serial communication, and is not limited to a power supply control IC. Generally applicable.

10, 20 Integrated circuit (power control IC)
DESCRIPTION OF SYMBOLS 11 Serial interface circuit 12,17 Register 13 Control circuit 14 Clock detection circuit 15 Switching circuit 16 Setting selection circuit 21 Function circuit 22 Terminal 100 Microcomputer Co capacitor L Inductor M1, M2 Switching element (N channel MOS transistor)
MP1, MP2 P-channel MOS transistor MN1 N-channel MOS transistor OP1 Operational amplifier circuit R0, R1, Rx resistance Rv Variable resistance

Claims (5)

A data input terminal for inputting data from the outside, a clock terminal for inputting a clock signal for controlling the input timing of the data, one or a plurality of address terminals, and input to the data input terminal A conversion circuit that converts a signal into a signal to an internal circuit, and a clock detection circuit that detects that the clock signal is input,
Until the clock detection circuit detects the clock signal, part or all of the output of the conversion circuit is switched to data based on the terminal state of the data input terminal and the address terminal. An integrated circuit characterized by processing.   A switching circuit that switches a part or all of the output of the conversion circuit and a part or all of data input to the data input terminal and the address terminal according to an output of the clock detection circuit; The integrated circuit according to claim 1.   A part of the output of the conversion circuit is a signal for setting a parameter relating to the operation of the integrated circuit, and part or all of the data input terminal and the address terminal until the clock detection circuit detects the clock signal. The integrated circuit according to claim 1, wherein the parameter is set by data based on a terminal state of the terminal.   The parameter set until the clock detection circuit detects the clock signal is based on a resistance value or a capacitance value of a resistor or a capacitor connected to a part or all of the data input terminal and the address terminal. The integrated circuit according to claim 3, wherein the integrated circuit is set as follows.   5. The integrated circuit according to claim 1, wherein the data is serial data, and the conversion circuit has a serial / parallel conversion function.