JP5483416B2 - LIGHT EMITTING ELEMENT DRIVE CIRCUIT SYSTEM AND ELECTRONIC DEVICE - Google Patents

Description

  The present invention relates to a light emitting element driving circuit system and an electronic apparatus, and more particularly, to a light emitting element driving circuit system for turning on and off a light emitting element at a certain timing and an electronic apparatus including the light emitting element driving circuit system.

  In recent years, a light emitting element driving circuit system is mounted on various electronic devices such as mobile phones. For example, Patent Literature 1 includes a drive current supply circuit that is connected in series to a light emitting element between a first power supply and a second power supply, and that supplies a drive current to the light emitting element in accordance with a voltage of a control terminal; A configuration is disclosed that includes a current determination circuit that determines and outputs a current according to the amount of light output from the light emitting element. When the control signal is in the first state, the current determined by the current determination circuit is converted into a voltage and output to the control terminal of the drive current supply circuit. When the control signal is in the second state, the output voltage terminal is A configuration including a current-voltage conversion circuit that disconnects from a control terminal of a drive current supply circuit is disclosed. And the structure which has the reset circuit which connects the control terminal of a drive current supply circuit to a 2nd power supply when a control signal is a 2nd state is disclosed.

JP 2008-251886 A

  By the way, a mobile phone or the like often displays characters / patterns on a liquid crystal screen or the like by emitting (lighting) a light emitting element (LED). Diversification of LED illumination expression is desired from the viewpoint.

  An object of the present invention is to provide a light-emitting element driving circuit system and an electronic apparatus including the light-emitting element driving circuit system that can realize diversification of LED illumination expressions more suitably.

Off-emitting element driving circuit system according to the present invention, to turn off the first lighting unit for lighting the light emitting element at a predetermined lighting color display period, said light-emitting element is unlit period longer than the lighting color display period a processing unit, by using the turn-off period, and a second lighting unit causes lighting the light emitting device in the lighting period longer than the lighting color display period, the off processing unit by an external control signal and a second lighting unit is characterized Rukoto switched.

  In addition, an electronic apparatus according to the present invention includes the above light emitting element driving circuit system.

  According to the light emitting element driving circuit system and the electronic apparatus having the above-described configuration, the light emitting element can be turned on at a lighting cycle different from the first cycle of the first lighting unit using the second cycle of the extinguishing unit. Thereby, since a light emitting element (LED) can be lighted by a 1st period and a 2nd period, diversification of LED illumination expression is realizable.

In an embodiment concerning the present invention, it is a figure showing a light emitting element drive circuit system. In embodiment which concerns on this invention, it is a program about the lighting pattern of the display part of 3 colors which consists of red LED, green LED, and blue LED set by the user.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In the following description, the LEDs constituting the display unit are described as being one for each color. For example, considering that human vision is dull with respect to the luminance of a green LED (G-LED), LEDs of the same color are used. May be used. For example, the number of green LEDs may be 2, and the number of LEDs of other colors may be provided one by one. Of course, it is good also as what increases the number of LED of colors other than green LED, and you may set the number to increase arbitrarily. As described above, the LEDs constituting the display unit may include LEDs of the same color, and a plurality of LEDs may be connected in parallel for one control. In addition, the type, color, number of colors, number, and the like of the light-emitting elements constituting the display portion can be changed as appropriate. In the following description, the same elements are denoted by the same reference symbols in all the drawings, and redundant description is omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram showing a light emitting element driving circuit system 10. The light emitting element drive circuit system 10 has a function of causing the display unit 50 to display a desired color by individually emitting the red LED 52, the green LED 54, and the blue LED 56 based on a setting program from a user or the like. The light emitting element drive circuit system 10 includes a normal OSC 12, a sleep OSC 22, a normal counter circuit 14, a sleep counter circuit 24, a selector circuit (MUX) 20, a drive command unit 30, and an LED drive unit 40. The setting circuit 60 is included. In the following description, it is assumed that the light emitting element drive circuit system 10 is mounted on a mobile phone and drives a red LED 52, a green LED 54, and a blue LED 56 that function as LED illumination of the mobile phone.

  The normal OSC 12 is an oscillation circuit that generates a reference clock having a high frequency (for example, 1 MHz). The reference clock generated by the normal OSC 12 is input to the normal counter circuit 14.

  The sleep OSC 22 is an oscillation circuit that generates a reference clock having a low frequency (for example, 64 KHz). The reference clock generated by the sleep OSC 22 is input to the sleep counter circuit 24.

The normal counter circuit 14 is an m-bit counter (m is an integer) that is counted up at the rising edge of the reference clock generated by the normal OSC 12. Therefore, the normal counter circuit 14 can count up from 0 to 2 ^m −1. Then, the normal counter circuit 14 generates a clock having a cycle T1 described later. The normal counter circuit 14 is described as being counted up at the rising edge of the reference clock from the normal OSC 12, but is counted up at the falling edge of the reference clock from the normal OSC 12. Also good.

The sleep counter circuit 24 is an n-bit counter (n is an integer) that is counted up at the rising edge of the reference clock generated by the sleep OSC 22. Therefore, the sleep counter circuit 24 can count up from 0 to 2 ⁿ −1. The sleep counter circuit 24 generates a clock having a cycle T2 to be described later. The sleep counter circuit 24 is described as being counted up at the rising edge of the reference clock from the sleep OSC 22, but is counted up at the falling edge of the reference clock from the sleep OSC 22. Also good.

  The setting circuit 60 acquires a program for the lighting pattern of the display unit 50 from the outside, and gives an instruction to the selector circuit 20 and the drive command unit 30 according to the procedure of the program. Although the setting circuit 60 is described as acquiring a program regarding an external lighting pattern, the setting circuit 60 may acquire setting information regarding an external lighting pattern and program the setting circuit 60 inside. .

  FIG. 2A illustrates the first program for the lighting pattern of the display unit 50 including the red LED 52, the green LED 54, and the blue LED 56. As shown in FIG. 2 (a), when the first program is executed, a lighting period is started first, followed by a lighting period, and then again a lighting period, a lighting period, a lighting period, a lighting period,. -The lighting period and the extinguishing period are repeated.

  Here, the lighting period is programmed so that the eight colors are switched and displayed on the display unit 50 at the cycle T1. In the example of the first program in FIG. 2A, “red” in the first cycle T1, “yellow” in the second cycle T1, “blue” in the third cycle T1, and “blue” in the fourth cycle T1. “Purple”, “White” in the fifth period T1, “Light blue” in the sixth period T1, “Orange” in the seventh period T1, and “Green” in the eighth period are displayed in color on the display unit 50. The lighting period ends, and the next light-off period is a state in which the display unit 50 is turned off (in other words, the sleep state of the display unit 50). Here, in the first program, the lighting pattern mode of the display unit 50 in the lighting period is referred to as a first lighting mode, and the lighting pattern mode of the display unit 50 in the lighting period is referred to as a light-off mode.

  FIG. 2 (b) shows a second program having a lighting pattern different from the first program shown in FIG. 2 (a). 2B and FIG. 2A are the first lighting mode in which the lighting pattern of the lighting period is the same, but the light-off period is not the light-off mode, and the display unit 50 has a period T2 different from the period T1. Is a program that displays “pink” on the screen. Here, the mode of the lighting pattern of the display unit 50 in the period T2 in the extinguishing period is referred to as a second lighting mode.

  The function of the setting circuit 60 will be described in detail with reference to FIGS. 2 (a) and 2 (b). When the first circuit shown in FIG. 2A is acquired from the outside, the setting circuit 60 outputs the clock of the period T1 output from the normal counter circuit 14 to the selector circuit 20 during the lighting period. A selection signal for selection is sent, and during the extinction period, a selection signal for selection so that the clock of the cycle T2 output from the sleep counter circuit 24 is output is sent. Then, the setting circuit 60 sends a control signal for causing the first lighting processing unit 32 to perform a driving command based on the first lighting mode to the driving command unit 30 to perform a driving command based on the first lighting mode. A control signal for causing the extinguishing processing unit 36 that performs a drive command to function is sent.

  Next, when the second program shown in FIG. 2B is acquired from the outside, the clock of the period T1 output from the normal counter circuit 14 is output to the selector circuit 20 during the lighting period. A selection signal for selection is sent, and during the extinction period, a selection signal for selection so that the clock of the cycle T2 output from the sleep counter circuit 24 is output is sent. Then, the setting circuit 60 sends a control signal that causes the first lighting processing unit 32 that performs a driving command based on the first lighting mode to function in the lighting period during the lighting period, and sets the second lighting mode in the lighting period. A control signal for causing the second lighting processing unit 34 to perform a driving command based on the function is sent.

  In response to the selection signal from the setting circuit 60, the selector circuit 20 sends either the clock of the cycle T 1 output from the normal counter circuit 14 or the clock of the cycle T 2 output from the sleep counter circuit 24 to the drive command unit 30. It is a selection circuit for selecting whether to output.

  Based on the control signal from the setting circuit 60, the drive command unit 30 performs switching control for the LED switching elements 41, 43, 45 of the LED drive unit 40 and LED current sources 42, 44, 46 of the LED drive unit 40. The drive current value is set. The drive command unit 30 includes a first lighting processing unit 32, a second lighting processing unit 34, and a turn-off processing unit 36.

  The first lighting processing unit 32 is a circuit that operates in response to a control signal from the setting circuit 60, and LEDs corresponding to the red LED 52, the green LED 54, and the blue LED 56 that need to emit light in order to display the color desired to be displayed on the display unit 50. The switching elements 41, 43, and 45 for use have a function of turning on with a clock having a cycle T1 output from the normal counter circuit 14. The first lighting processing unit 32 has a function of setting the drive current values of the LED current sources 42, 44, and 46 that cause the drive currents to flow through the red LED 52, the green LED 54, and the blue LED 56, respectively.

  The second lighting processing unit 34 is a circuit that operates in response to a control signal from the setting circuit 60. Like the first lighting processing unit 32, the switching control of the LED switching elements 41, 43, 45, and the LED current source are performed. It has a function of setting each drive current value of 42, 44, and 46. However, unlike the first lighting processing unit 32, the second lighting processing unit 34 is not a clock having a cycle T1 output from the normal counter circuit 14, but a clock having a cycle T2 output from the sleep counter circuit 24. Switching control of the LED switching elements 41, 43, 45 is performed.

  The turn-off processing unit 36 is a circuit that operates according to a control signal from the setting circuit 60, and turns off all the LED switching elements 41, 43, and 45 in order to turn off the red LED 52, the green LED 54, and the blue LED 56 of the display unit 50. It has a function of controlling or setting the current value of the LED current sources 42, 44, 46 to zero. Note that the extinguishing processing unit 36 counts the sleep period with the clock of the cycle T2 output from the sleep counter circuit 24 in the extinguishing mode of the first program.

  The LED drive unit 40 includes LED switching elements 41, 43, 45 and LED current sources 42, 44, 46. The LED switching elements 41, 43, and 45 are switching elements that are on / off controlled by the drive command unit 30, and are configured using, for example, transistors. The LED current sources 42, 44, 46 are current sources for driving the red LED 52, the green LED 54, and the blue LED 56 with the drive current value set by the drive command unit 30.

  The LED switching element 41 has one end connected to the power source and the other end connected to the anode terminal of the red LED 52. The LED current source 42 has one end connected to the cathode terminal of the red LED 52 and the other end grounded. The LED switching element 43 has one end connected to the power source and the other end connected to the anode terminal of the green LED 54. The LED current source 44 has one end connected to the cathode terminal of the green LED 54 and the other end grounded. The LED switching element 45 has one end connected to the power source and the other end connected to the anode terminal of the blue LED 56. The LED current source 46 has one end connected to the cathode terminal of the blue LED 56 and the other end grounded.

  The display unit 50 includes a red LED 52, a green LED 54, and a blue LED 56, and is provided outside the light emitting element driving circuit system 10. These LEDs are circuit elements that emit light when a voltage is applied to the anode terminal (anode) in the forward direction with respect to the cathode terminal (cathode). The red LED 52 has an anode terminal connected to the other end of the LED switching element 41 and a cathode terminal connected to one end of the LED current source 42. The green LED 54 has an anode terminal connected to the other end of the LED switching element 43 and a cathode terminal connected to one end of the LED current source 44. The blue LED 56 has an anode terminal connected to the other end of the LED switching element 45 and a cathode terminal connected to one end of the LED current source 46. The red LED 52, the green LED 54, and the blue LED 56 have been described as being provided outside the light emitting element driving circuit system 10, but may be provided inside the light emitting element driving circuit system 10.

  The operation of the light emitting element driving circuit system 10 having the above configuration will be described with reference to FIGS. When the first program shown in FIG. 2A is acquired from the outside, when the first program is executed, first, during the lighting period, “red”, “yellow”, “blue”, “purple”, “white”, “light blue” In the order of “orange” and “green” colors, the display unit 50 switches the colors at the cycle T1 and displays the colors. During the turn-off period after the turn-on period, the red LED 52, the green LED 54, and the blue LED 56 of the display unit 50 are turned off at a cycle T2. Then, during the lighting period after the extinguishing period, the respective colors are displayed in the display unit 50 in the order of the colors as described above, with the period T1 being switched.

  In addition, when the second program shown in FIG. 2B is acquired from the outside due to a setting change of the user or the like, the lighting period is the same color pattern of the first lighting mode as in FIG. Is displayed and displayed in color at the cycle T1, and “pink” is displayed in color at the cycle T2 on the display unit 50 during the extinguishing period after the lighting period. Here, the cycle T1 is a clock output by the normal counter circuit 14 counted up by the high speed clock, and the cycle T2 is a period output by the sleep counter circuit 24 counted up by the low speed clock. The period T2 has a longer period than the period T1.

  As described above, according to the light emitting element driving circuit system 10, different colors are displayed on the display unit 50 as illustrated in FIG. 2B by using the extinguishing period (extinguishing mode) illustrated in FIG. Can be displayed. That is, by switching from the first program to the second program, the extinguishing mode can be switched to the second lighting mode. Thereby, the second program shown in FIG. 2 (b) can display one color more than the lighting pattern in the first program shown in FIG. 2 (a). Diversification can be realized. In addition, although the said Example demonstrated the case where it applied to LED illumination, naturally it is also possible to apply to the LED backlight of a liquid crystal screen.

  In addition, the display unit 50 displays the color using the extinguishing period. Accordingly, since the color can be displayed with a lighting cycle T2 different from the normal lighting cycle T1, for example, the LED backlight and the LED illumination of the liquid crystal screen of the mobile phone can be controlled by separate drive circuit systems. Although it is general, if the present invention is used, it is possible to control the LED backlight and the LED illumination of the liquid crystal screen of the mobile phone with one light emitting element driving circuit system, and in this case, various colors are expressed. The illumination pattern can be expressed by the first lighting mode, and when the illumination pattern is not lit (in other words, when the backlight color of the liquid crystal screen is displayed), it can be expressed by the second lighting mode. Therefore, the backlight color of the liquid crystal screen can be set independently of the illumination pattern. Furthermore, by assigning the illumination pattern and the backlight color of the liquid crystal screen separately to the first lighting mode and the second lighting mode, respectively, the illumination pattern and the backlight color of the liquid crystal screen can be managed independently. Therefore, there is an effect that management becomes easy.

  DESCRIPTION OF SYMBOLS 10 Light emitting element drive circuit system, 12 normal OSC, 14 normal counter, 20 selector circuit, 22 sleep OSC, 24 sleep counter circuit, 30 drive command part, 32 1st lighting process part, 34 2nd lighting process part 36, extinction processing unit, 40 LED driving unit, 41, 43, 45 LED switching element, 42, 44, 46 LED current source, 50 display unit, 52 red LED, 54 green LED, 56 blue LED, 60 setting circuit .

Claims (2)

A first lighting processing unit for lighting a light emitting element in a predetermined lighting color display period ;
And off processing unit for turning off said light-emitting element is unlit period longer than the lighting color display period,
Using the extinction period, a second lighting unit causes lighting the light emitting element at a lighting period of longer than the lighting color display period,
With
Light-emitting element driving circuit system characterized Rukoto are switched and the off processing unit and the second lighting unit by a control signal from the outside. An electronic apparatus comprising the light-emitting element drive circuit system according to claim 1 .

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