JP2007306073A - Semiconductor system and mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that an exclusive terminal is required to a power supply control instruction of a power supply IC comprising an LSI and furthermore the serial control is added to an I2C bus or the like, thereby preventing miniaturization and the commercial value of the mobile terminal cannot be increased because flexible reset control (an initial state of an external interface is maintained and only an internal state of the LSI is initialized) of the mobile terminal is not executed. <P>SOLUTION: The LSI 100 transmits information (internal reset information or the like of the LSI 100) to the power supply IC 200 depending on a serial terminal state different from a state of an ordinary serial communication format. Thus, the terminals are shared and the terminal state including reset is immediately delivered to the power supply IC 200. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a semiconductor system and a portable terminal having the semiconductor system, and in particular, the semiconductor system according to the present invention uses an LSI capable of controlling a power supply IC by serial communication and feeding back a reset control state to the power supply IC, and a power supply IC. ing.

  In a mobile terminal such as a mobile phone, miniaturization of the terminal and extension of operation time due to a built-in battery are indispensable issues for increasing the commercial value of the terminal.

  Here, the external interface of the terminal (for example, a display or a keypad) is limited by the physical size requirement of the terminal user (human), so it is built in to solve the miniaturization of the terminal. It is required to reduce the size of members (LSI, power supply IC, battery, etc.). Furthermore, in order to extend the operating time of the terminal, the operating power of various functions realized by the terminal is reduced (reducing operating voltage, reducing operating current), and the battery is not wasted when it is not functioning. (Reduction of power consumption during standby) is required.

  In order to solve these points, for example, by integrating functions in an LSI by miniaturizing a semiconductor process, it is possible to reduce the size and reduce the operating power per function. However, since the operating voltage decreases due to miniaturization, efficient voltage conversion from the battery voltage by the power supply IC is necessary, and further, the leakage current increases exponentially as the threshold voltage of the transistors constituting the LSI decreases. Therefore, a new measure for preventing the standby current from increasing is necessary. When the LSI is miniaturized, the package becomes smaller, so the signal path (number of terminals) used for the external interface is also restricted.

  Therefore, in Conventional Example 1 (see Patent Document 1), the LSI is divided by function, and the leakage current is eliminated by turning off the power supply of the block that does not require the function. In Conventional Example 2 (see Patent Document 2), in order to use the built-in battery unit efficiently, the power supply IC (power supply control unit) has a plurality of operation modes, so that both the functional operation and the standby current can be reduced. I am trying. In setting this operation mode, using serial communication by the I2C bus (see Non-Patent Document 1) helps to reduce the signal path (number of terminals) connecting the LSI and the battery unit.

  Further, the power supply IC not only supplies power from the battery to the LSI, but also serves as a master for the entire semiconductor system that performs reset control of the LSI. This is because when the power supply from the power supply IC to the LSI is started, the LSI itself must be uniquely initialized by resetting the LSI. In this initialization state, functions such as the I2C bus controlled by the program execution of the CPU built in the LSI are not yet usable. However, a Bit-IO (dedicated terminal) that can uniquely fix the state by initialization can be used.

  Also, on the premise that the reset state of the LSI is unique, it is not usually fed back to the power supply IC. For example, when a plurality of CPUs and function blocks are provided inside, the individual power state and reset Although states may exist, they are not actively used, only simple determination of whether or not to reset, and flexible reset control of the mobile terminal (for example, the external interface remains This state is maintained and only the internal state of the LSI is initialized).

  FIG. 2 shows a block diagram of a conventional semiconductor system based on the above various examples. In FIG. 2, the components and their operations are the same as the corresponding parts in the first embodiment to be described later.

  In the conventional example, Bit-IO (dedicated terminal) is used for power control at the start of power supply, and LSI reset control is unilaterally performed from the power IC to the LSI.

JP 2003-209616 A JP 11-191931 A I2C Bus Specification Version 2.1 January 2000; Philips Semiconductors

  However, as described above, a bit-IO (dedicated terminal) is necessary for the power supply control instruction of the power supply IC by the LSI, and the signal path ( In order to cope with the increase in the number of terminals) and the flexibility of functions, there is a problem that it is contrary to miniaturization, such as adding serial control such as an I2C bus.

  Further, LSI reset control is performed unilaterally from the power supply IC, and feedback of the situation when a plurality of functional blocks are provided inside the LSI cannot be performed to the power supply IC. Is kept as it is, and only the internal state of the LSI is initialized), and there is a problem that it is difficult to increase the commercial value as a portable terminal.

  The present invention has been made based on recognition of such problems, and its purpose is to realize a portable terminal that can contribute to the miniaturization of a portable terminal without increasing the number of terminals and that has increased commercial value. It is to provide a semiconductor system that can be made possible.

  The subject of the present invention is a semiconductor system comprising a power supply IC and an LSI having a serial communication function, wherein information is sent from the LSI to the power supply IC in a serial terminal state different from a normal serial communication format. To do.

  Hereinafter, various embodiments of the subject of the present invention will be described in detail along with the effects and advantages thereof with reference to the accompanying drawings.

  According to the subject of the present invention, it is possible to contribute to the realization of downsizing of the portable terminal without increasing the number of terminals, and the internal reset state can be monitored, so that the consistency and stability of the terminal state including reset can be ensured. In addition, it is possible to realize a mobile terminal with increased product value. Therefore, an inexpensive portable terminal with stable operation can be realized.

  The present invention relates to a semiconductor system including a power supply IC and an LSI having a serial communication function, and a portable terminal further including a battery (not shown) and an external interface (not shown). Information is sent from the LSI to the power supply IC in a serial terminal state different from the format. Hereinafter, Embodiment 1 which embodies the present invention will be described with reference to the drawings.

(Embodiment 1)
In the present embodiment, the power supply control instruction of the power supply IC by the LSI is serially communicated using only the IC2 bus in a format (second level) different from the normal format (first level). In addition, information regarding the reset control state in the LSI is also fed back to the power supply IC side by serial communication using only the IC2 bus in different formats. Such a feature makes it possible to easily transmit a power control instruction and a reset control state from the LSI to the power IC. Hereinafter, reference is made to the drawings.

  FIG. 1 is a block diagram schematically showing a configuration example of a semiconductor system and a mobile terminal according to the present embodiment.

  In FIG. 1, a mobile terminal 300 is mainly composed of an LSI 100, a power supply IC 200, a battery (not shown), an external interface (not shown), and the like.

  Among these, the LSI 100 includes a CPU 1, a Bit-IO (dedicated terminal) 2, an I2C serial control circuit (master side) 3, a reset execution circuit 4, a control circuit 5, and an internal bus 6. To realize the functions of the mobile terminal.

  In the LSI 100, the CPU 1 is a central processing unit that controls the whole or a part of the LSI 100 (when a plurality of CPUs are provided) by executing programs stored in various storage elements (not shown).

  Bit-IO (dedicated terminal) 2 is initialized by reset execution of LSI 100, and its terminal state can be changed by program execution of CPU 1. The terminal state is transmitted to each element in the LSI 100 and the outside of the LSI 100.

  The I2C serial control circuit (master side) 3 is a circuit for controlling a known I2C bus (signal path). The I2C bus (signal path) controlled by the circuit 3 is composed of two bidirectional signal lines (serial clock SCL and serial data SDA). In this embodiment, the I2C bus is used as a serial communication format. Details of the I2C bus are as described in the specification document of Non-Patent Document 1. As described in the specification, the I2C bus is a bidirectional bus consisting of two wires (serial clock SCL and serial data SDA) for the purpose of efficient control between ICs. Also referred to as an inter-IC mutual bus. Information transmission between the devices connected to the bus is executed by the two wires. Here, the “master” is a device that starts data transfer on the bus, and generates a clock signal that enables transfer. At that time, the device addressed by “master” becomes “slave”.

  The reset execution circuit 4 performs reset execution of the entire LSI 100.

  The control circuit 5 performs overwriting control of the state of the I2C bus controlled by the I2C serial control circuit (master side) 3 according to the output state of the reset execution circuit 4 and the Bit-IO (dedicated terminal) 3.

  Further, the internal bus 6 is used as a signal path for the CPU 1 to control the Bit-IO (dedicated terminal) 2, the I2C serial control circuit (master side) 3, the reset execution circuit 4, and the like by a program.

  On the other hand, the power supply IC 200 secures the consistency and safety of the entire mobile terminal 300 by collectively realizing power supply and reset control of the semiconductor system.

  Among the components of the power supply IC 200, reference numeral 21 is a power supply control circuit, and the circuit 21 supplies power to the LSI 100 from a battery (not shown) at a necessary voltage or current.

  The I2C serial control circuit 22 is a slave side when the I2C serial control circuit (master side) 3 takes the initiative in executing various serial communications using the I2C bus (signal path). See Non-Patent Document 1 for details of the I2C bus.

  The reset control circuit 23 mainly sets the LSI 100 to an initial state.

  Next, the operation of the semiconductor system will be described with reference to FIG.

  The portable terminal 300 is activated by an input from a keypad (power key) (not shown) to the power supply IC 200. The LSI 100 is reset by the reset control circuit 23 of the power supply IC 200 at startup. That is, the reset execution inside the LSI 100 is performed by the reset execution circuit 4.

  In the control circuit 5, the reset execution circuit 4 changes the SDA output of the I2C serial control circuit (master side) 3 (normally H level (first level) at reset) to L level (second level) different from the normal format. Control overwriting. As a result, the LSI 100 serially transmits LSI internal reset information to the power supply IC 200 side in a serial terminal state (L level) different from the normal serial communication format.

  The L level indicating the LSI internal reset control state is observed by the I2C serial control circuit (slave side) 22 to recognize that the LSI 100 is currently performing the reset operation. Based on this recognition result, the reset control circuit 23 on the power supply IC 200 side can perform power control at the time of reset more flexibly (timing adjustment, etc.). Then, the reset control circuit 23 releases the reset to the LSI 100 thereafter.

  When the reset is released, the reset execution circuit 4 finishes the overwriting control for the control circuit 5 (returns the serial data SDA to the normal H level). As a result, the I2C serial control circuit (master side) 3 and the I2C serial control A normal power supply control with a normal serial communication format can be executed with the circuit (slave side) 22.

  Next, in the normal operation state of the mobile terminal 300, for example, the CPU 1 stops the program execution due to low power consumption, and the power supply IC 200 cannot be controlled using the I2C serial control circuit (master side) 3. Think about the state. In this case, preparation settings (the serial clock SCL is different from the normal format at the L level (second level) in advance in the internal control register (not shown) of the power supply control circuit 21 of the power supply IC 200 by I2C serial control. The power supply is resumed when the level reaches the level), and then a simple sequencer (not shown) using a constant operation timer or the like using a real-time clock (32.768 kHz) in the LSI 100 is used. (Dedicated terminal) 2 is changed (for example, changed from normal H level to L level), and the output of the serial clock SCL of the I2C bus is overwritten through the control circuit 5 to control the normal H level. To L level. The information of the power supply control instruction for the power supply IC 200 is serially transmitted from the LSI 100 side to the power supply IC 200 side via the I2C bus according to different serial terminal states (change to L level), and the information is I2C serial control circuit (slave side) 22 As a result, the operating state of the power supply control circuit 21 can be changed (resumption of power supply, etc.).

  Further, when the power supply IC 200 does not perform reset execution or the above-described preparation setting, the output change of the serial data SDA different from the normal format (for example, the state where the START condition and the STOP condition of the I2C bus are continuously executed) Is monitored by the I2C serial control circuit (slave side) 22, the power supply IC 200 determines that an abnormal operation such as execution of internal reset has been performed in the LSI 100, and the power supply IC 200 performs the corresponding power supply control and reset control. Can be executed immediately.

  As described above, according to the present embodiment, the control circuit 5 does not use the Bit-IO (dedicated terminal) 2 to send a power supply control instruction of the power supply IC 200 or feedback to the power supply IC 200 for reset control of the LSI 100. It can be executed with only the I2C bus between both circuits 3 and 22 to be overwritten, and as a result, it is possible to contribute to miniaturization of the portable terminal 300 without increasing the number of terminals. In addition, since the reset state in the LSI 100 can be monitored on the power supply IC 200 side by feedback via the I2C bus, the consistency and stability of the terminal state including reset can be ensured, and the mobile terminal 300 with enhanced commercial value can be obtained. There is an effect that it can be realized.

  In the above embodiment, both the information on the power supply control instruction of the power supply IC 200 by the LSI 100 and the feedback to the power supply IC 200 in the reset execution state inside the LSI 100 are transmitted and executed using the I2C bus. Only one of these pieces of information may be realized as described above, and another serial bus may be used instead of the I2C bus.

  Furthermore, in the example of the above embodiment, the I2C bus is used as the serial communication format, but instead of this, other formats, that is, a normal communication format such as a general three-wire serial or μ-wire, are used. (I.e., other states are exceptional states) may be serial communication.

(Appendix)
While the embodiments of the present invention have been disclosed and described in detail above, the above description exemplifies aspects to which the present invention can be applied, and the present invention is not limited thereto. In other words, various modifications and variations to the described aspects can be considered without departing from the scope of the present invention.

  The present invention is suitably used for a mobile terminal using a power supply IC and an LSI, for example, a terminal device such as a mobile phone.

It is a block diagram which shows the semiconductor system and portable terminal which concern on Embodiment 1 of this invention. It is a block diagram which shows the semiconductor system and portable terminal which concern on a prior art.

Explanation of symbols

1 CPU, 2 Bit-IO (dedicated terminal), 3 I2C serial control circuit (master side), 4 reset execution circuit, 5 control circuit, 6 internal bus, 21 power supply control circuit, 22 I2C serial control circuit (slave side), 23 Reset control circuit, 100 LSI, 200 power supply IC, 300 portable terminal.

Claims (5)

In a semiconductor system consisting of a power supply IC and an LSI having a serial communication function,
Sending information from the LSI to the power supply IC by a serial terminal state different from a normal serial communication format,
Semiconductor system. The semiconductor system according to claim 1,
The information from the LSI is power control information for the power IC.
Semiconductor system. The semiconductor system according to claim 1,
The information from the LSI is internal reset information of the LSI,
Semiconductor system. A semiconductor system according to any one of claims 1 to 3,
I2C bus is used as a serial communication format,
Semiconductor system. The semiconductor system according to any one of claims 1 to 4,
Battery,
An external interface, and
Mobile device.

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