JP6170803B2 - Illuminated cane - Google Patents

Description

The present invention relates to an illuminated cane provided with a battery in which voltage fluctuation occurs as an operating power source.

  A microprocessor mounted on a device including a battery as an operation power supply can function as a processor as long as the voltage of the battery as a power supply fluctuates as long as it is within an operable fluctuation range.

  However, the A / D converter built in the microprocessor cannot function at all in the power supply system in which the voltage fluctuates. The built-in A / D converter requires a reference voltage source that never fluctuates and needs to be lower than the power supply voltage of the processor.

  In a system in which the power supply voltage is constant, the reference voltage of the processor built-in A / D converter is generally used as a value equal to the power supply voltage. However, in the case of a microprocessor mounted on a device including a battery as an operation power supply, fluctuations in the power supply voltage cannot be avoided, and thus such a general method of use cannot be adopted.

Assume that the circuit configuration is made by making the reference voltage of the processor built-in A / D converter equal to the power supply voltage (battery voltage). At this time, for example, when a 10-bit A / D converter is mounted and the power supply voltage changes in the range of +4.2 V to +2.5 V, the intermediate value of the analog input value is as follows.
When the power supply voltage value is + 4.2V, the intermediate value is + 2.1V. The binarized data of the intermediate value + 2.1V is $ 1FF. When the power supply voltage value is + 3.0V, the intermediate value is + 1.5V. This binarized data of intermediate value + 1.5V is also $ 1FF.

  Despite being different intermediate values, the binarized data is the same $ 1FF. Since the actual analog input value is not fixed and there are almost infinite combinations, it does not function as an A / D converter as a result.

  By the way, there are many requests to know how many values of the power supply voltage are in an apparatus equipped with a battery as an operation power supply.

  If the above power supply voltage is adopted as the reference voltage, the digital conversion value of the power supply voltage is always the maximum value of $ 3FF when the built-in A / D converter is 10 bits, and a true value can be obtained. Can not.

  To cope with this problem, microprocessors that use built-in A / D converters usually use a DC-DC converter, which is a voltage conversion circuit, from a battery power supply, and then configure this fixed voltage system once. Treat the processor in a voltage supply.

  The voltage value converted by the DC-DC converter is set higher or lower than the battery voltage depending on the circuit application and system. In the case of a lower setting, the voltage may be stepped down using a three-terminal regulator.

  However, the three-terminal regulator is not efficient because it simply converts the step-down voltage into heat. On the other hand, a DC-DC converter cannot be 100% efficient, and battery power is wasted.

  In the battery power supply system, it is competing to configure the electric power possessed by the battery with maximum efficiency without waste. Otherwise, frequent battery replacement and charging are required.

  As a matter of course, the voltage conversion circuit requires a considerably large cost and a mounting area in a DC-DC converter circuit with particularly high efficiency.

  As described above, the three-terminal regulator consumes a large amount of battery power, and requires a heat exhausting structure with an appropriate amount of heat generation.

  In addition, as a device including a battery in which voltage fluctuation occurs as an operation power source, a walking stick that supports a pedestrian's body and supports walking, and is equipped with a lighting light is known.

JP 2008-302006 A

  In a device provided with a battery in which voltage fluctuation occurs as an operation power supply, the operation of the device is hindered when the remaining amount of the battery decreases. For example, in the case of a cane with illumination, if the remaining battery level is low, the amount of light from the lamp is reduced and sufficient illumination cannot be performed. The battery may run out during walking and the lamp may turn off.

An object of the present invention is to provide an illuminated cane equipped with a voltage monitoring device that can accurately detect the voltage of a battery in which voltage fluctuation occurs without consuming as much power as possible.

The illuminated cane of the present invention has a battery in which voltage fluctuation occurs as an operating power source, and has first and second light emitting diodes having different emission colors as light emitting means that operate by the power of the battery, and includes a light on / off switch. of the battery; a lighted wand having associated, as input voltage E of the battery, the reference voltage IC and the upper limit to output a weak current of about 2mA outputs a reference voltage Eref lower than the input voltage E A voltage dividing means for outputting the voltage E as a voltage Ed by voltage division and having a voltage dividing ratio set so that the maximum value Edmax of the output voltage Ed accompanying the voltage fluctuation of the battery becomes the same value as the reference voltage Eref ; The output voltage Ed of the voltage dividing means is subjected to analog / digital conversion based on the reference voltage Eref, and the value obtained by this analog / digital conversion is used as the maximum voltage fluctuation of the battery. Corrected by the ratio "Emax / Eref" between the value Emax and a value of the reference voltage Eref, a calculating means captures the value obtained by this correction as the value of the voltage E of the battery; and a voltage monitoring device which includes a lighting / A first control means for turning on the first light emitting diode to illuminate the periphery of the illuminated cane when the value of the captured voltage E is not less than a predetermined value E2 when the extinction switch is on; When the value of the captured voltage E is greater than or equal to a set value E1 and less than the predetermined value E2, the first light emitting diode is turned on to illuminate the area around the illuminated cane and the remaining battery level The second control means for intermittently turning on the second light emitting diode for a certain period of time to notify that the current is half, and the value of the captured voltage E is the set value E1 when the on / off switch is on. Less than A third control means for turning on the second light emitting diode only when off the first light emitting diode intermittently on shiso the first light emitting diode in order to notify that the remaining amount of the battery is scant And fourth control means for setting an operating current when the first light emitting diode is turned on to a current smaller than a rated current of the first light emitting diode when the first light emitting diode is intermittently turned on.

The figure which shows the whole structure of one Embodiment. The figure which shows the structure of the illumination part of one Embodiment in cross section. The figure which shows the cross section which follows the AA line of FIG. The block diagram which shows the control circuit of one Embodiment. The figure which shows the structure of the microprocessor in the control circuit of FIG. 4, and its peripheral part. The flowchart which shows the control of one Embodiment. The time chart which shows ON / OFF of each light emitting diode of one Embodiment. The figure which shows the external appearance of the components mounted in the printed circuit board of one Embodiment, and the printed circuit board. The block diagram which shows the structure of the modification of the control circuit of one Embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a cane body, which is attached to a support column 2 formed in a cylindrical shape with lightweight aluminum or carbon fiber, a wooden handle 3 attached to the upper end of the support 2, and a lower end of the support 2. It has the resin stone thrust part 4 made. The column portion 2 has a leg portion 2a for length adjustment that can be pulled out and stored on the lower end side, and a fixing screw 2b at a boundary portion with the leg portion 2a. The leg 2a can be expanded and contracted by loosening the fixing screw 2b, and the expansion and contraction position of the leg 2a can be fixed by tightening the fixing screw 2b. The stone thrusting part 4 is located at the tip of the leg part 2a, and absorbs an impact when it strikes the walking surface.

  The leg part 2a of the column part 2 includes the illumination part 5 formed in a cylindrical shape with a colorless and transparent light-transmitting member as a part of the leg part 2a. The inner peripheral surface of the illuminating unit 5 is divided into an upper inner peripheral surface 5a and a lower inner peripheral surface 5b along the axial direction of the support column 2 as shown in a cross section in FIG.

  The printed circuit board 8 is fitted and held on the inner peripheral surface of the leg 2a at the upper part in the illumination unit 5. On the lower surface side of the printed circuit board 8, light emitting means such as a light emitting diode (LED: first light emitting means) 51 and a light emitting diode (LED: second light emitting means) 52 are arranged facing downward. The light emitting diode 51 emits white (also referred to as cool white) or daylight (also referred to as warm white) light, and functions as a main light for illumination. The light emitting diode 51 emits blue to green light and functions as an auxiliary light.

  The upper inner peripheral surface 5a of the illuminating unit 5 transmits the light from the light-emitting diodes 51 and 52 in the circumferential direction (perpendicular to the axial direction) of the support column 2 as shown in FIG. Optically refraction shapes that expand and diffuse in the direction of the surface, for example, cylindrical lens-shaped curved surfaces, are arranged in order in the circumferential direction. Light emitted from the light-emitting diodes 51 and 52 and entering the curved surface shape of the cylindrical lens shape is enlarged in the circumferential direction of the column part 2 and transmitted through the illumination unit 5, and is almost enlarged (refracted) in the axial direction of the column part 2. ) Is transmitted through the illumination unit 5 without being performed. That is, when the support column 2 is upright on the ground, the light emitted from the illuminating unit 5 simply spreads to a predetermined range at the center of the stone bump 4 as shown by a two-dot chain line in FIG. It spreads upward and does not dazzle others' eyes. This is a so-called antiglare effect.

  The lower inner peripheral surface 5b of the illuminating unit 5 is a simple curved surface having no optical refractive shape, and totally reflects most of the light reaching from the upper light emitting diodes 51 and 52 downward. This is also for anti-glare. However, since the material of the illumination unit 5 is transparent, the inside of the illumination unit 5 looks dark and bright.

  A hand-held strap 7 is attached to a boundary portion between the support column 2 and the handle portion 3 via a belt 6. In the vicinity of the belt 6 in the support column 2, a push button operation type on / off switch 11 for designating on / off of the light emitting diode 51, a light emitting body for notifying a charged state of the battery described later, for example, the light emitting diode 12, A plug insertion type charging terminal (also referred to as a DC jack) 13 is arranged in the axial direction. The on / off switch 11 is repeatedly turned on and off each time it is pressed, and is not limited to a push button type but may be an alternate type slide switch. A charging plug of a charger (also referred to as an AC adapter) prepared as an accessory of the cane body 1 is inserted and connected to the charging terminal 13. The charger converts the voltage of the commercial AC power source into a DC voltage of a predetermined level for charging and outputs the voltage.

  In the cane body 1 having such a configuration, a control circuit for driving and controlling the light emitting diodes 51 and 52 is accommodated in the support column 2. This control circuit is shown in FIG.

  A charging control circuit 22 is connected to the charging terminal 13 via a protection circuit 21. The protection circuit 21 performs overvoltage protection, low voltage protection, reverse connection protection, and the like on the input voltage from the charging terminal 13. The current fuse 61, reverse connection protection circuit 62, overvoltage protection circuit 63, and load switch circuit 64 are provided. Have In the current situation where there are a large number of AC adapters for charging in the home, it is possible to use things other than those attached to the illuminated cane, and these overvoltage protection, low voltage Protection and reverse connection protection are adopted.

  The current fuse 61 cuts off the energization path when an excessive current flows due to a failure on the load side. The reverse connection protection circuit 62 addresses the fact that various charging AC adapters of different types from the charger attached to the wand body 1 are distributed in the polarity of the voltage (the relationship between the positive electrode and the negative electrode). When an input voltage having a polarity different from that of the battery charger attached to the main body 1 is detected, it is detected as reverse connection. The overvoltage protection circuit 63 detects an input voltage higher than the rated voltage as an overvoltage. When the reverse connection protection circuit 62 detects reverse connection and when the reverse connection protection circuit 62 detects an overvoltage, the load switch circuit 64 cuts off the energization path for the subsequent charge control circuit 22.

  The charge control circuit 22 charges the DC voltage input from the charging terminal 13 via the protection circuit 21 to the rechargeable lithium ion battery 23 of one cell by the constant current constant voltage (CCCV) method, and the charge state Is notified by the attached light emitting diode 12. The light emitting diode 12 emits red light, for example, and lights up when a charging voltage is supplied to the lithium ion battery 23.

  The lithium ion battery 23 outputs a DC voltage (drive power) E for driving the light emitting diodes 51 and 52. A drive control unit 24 is connected between a positive terminal and a negative terminal of the lithium ion battery 23, and light emitting diodes 51 and 52 are connected to the drive control unit 24. The lithium ion battery 23 has various protection circuits such as overcharge protection, overdischarge protection, overcurrent protection, and abnormally high temperature protection, and a release vent. Even when the function of the protection circuit 21 is lost, the lithium ion battery 23 has an abnormally high temperature. Can be avoided from expansion, rupture, explosion and ignition.

  The drive control unit 24 controls the driving of the light emitting diodes 51 and 52 by the voltage E of the lithium ion battery 23. The drive control unit 24 includes a microprocessor 70 as a calculation unit, a load disconnect circuit 71, a current fuse 72, a reference voltage IC 73, a load. It has a switch circuit 74, a main LED drive circuit 75, and an auxiliary LED drive circuit 76.

  The load disconnection circuit 71 detects the insertion connection of the charging plug to the charging terminal 13 based on the output of the third contact of the charging terminal 13, and the drive control unit from the lithium ion battery 23 when the charging plug is not inserted. The energization path to 24 is formed, but the energization path from the lithium ion battery 23 to the drive control unit 24 is interrupted when the charging plug is inserted and connected. The current fuse 72 cuts off the energization path when an excessive current flows due to a failure on the load side.

  The reference voltage IC 73 is a low power consumption type reference voltage source that receives the voltage E of the lithium ion battery 23 and outputs a reference voltage Eref having a value lower than the input voltage E. The fluctuation range of the voltage E of the lithium ion battery 23 is, for example, + 4.2V to + 2.72V. In other words, the reference voltage IC73 is a semiconductor integrated circuit that accurately outputs and outputs a reference voltage Eref of, for example, + 2.5V, which is lower than the lower limit value + 2.72V of the fluctuation range of the battery voltage E, and has an upper limit of about 2 mA. This is different from general DC-DC converters and three-terminal regulators. In the case of a DC-DC converter, an attempt to improve the conversion efficiency results in an increase in cost and an increase in mounting area. The three-terminal regulator steps down and outputs an input voltage, and the step-down amount is simply converted into heat, so the efficiency is low and power is wasted. Compared to these DC-DC converters and three-terminal regulators, the reference voltage IC 73 is characterized by low cost, small size, space saving, low power consumption, and no burden on the lithium ion battery 23.

  The load switch circuit 74 is interposed in an energization path from the lithium ion battery 23 through the load disconnection circuit 71 and the current fuse 72 to the main LED drive circuit 75 and the auxiliary LED drive circuit 76, and the energization path is commanded from the microprocessor 70. Open and close according to.

  The main LED drive circuit 75 drives the light emitting diode 51 by the battery voltage E input through the load switch circuit 74 and in response to a command from the microprocessor 70. The auxiliary LED driving circuit 76 drives the light emitting diode 52 by the battery voltage E input through the load switch circuit 74 and in response to a command from the microprocessor 70.

The configuration of the microprocessor 70 and its peripheral part is shown in FIG.
That is, the battery voltage E that has passed through the load cutting circuit 71 and the current fuse 72 is applied to the power supply terminals of the microprocessor 70 and the reference voltage IC 73, respectively, and to the series circuit of the resistors R1 and R2. The reference voltage Eref of the reference voltage IC 73 is input to the reference voltage terminal of the microprocessor 70.

  The series circuit of the resistors R1 and R2 is a voltage divider (voltage dividing means) that divides and outputs the battery voltage E by resistance division, and outputs the voltage Ed generated in the resistor R2. This output voltage Ed is input to the monitoring voltage terminal of the microprocessor 70. In particular, with regard to the resistors R1 and R2, the voltage dividing ratio is set so that the maximum value Edmax of the output voltage Ed accompanying the voltage fluctuation of the lithium ion battery 23 becomes the same value as the reference voltage Eref.

The microprocessor 70 has the following means (1) to (6) as main functions.
(1) Analog / digital conversion means for analog / digital (A / D) conversion of the input voltage Ed from the voltage divider based on the reference voltage Eref.

  (2) Correction means for correcting the value obtained by analog / digital conversion by the ratio “Emax / Eref” between the maximum value Emax of the voltage fluctuation of the lithium ion battery 23 and the value of the reference voltage Eref. As described above, the fluctuation range of the voltage E of the lithium ion battery 23 is, for example, + 4.2V to + 2.72V, and + 4.5V having a margin in + 4.2V is defined as the maximum value Emax (constant), + 2.7V with a margin of + 2.72V is defined as the minimum value Emin (constant).

  (3) Detection means for capturing the value obtained by the above correction as the value of the voltage E of the lithium ion battery 23 (the remaining amount of the lithium ion battery 23) when the on / off switch 11 is on.

  (4) When the value of the captured battery voltage E is equal to or greater than the set value E1, the light-emitting diode 51, which is the main lamp, is turned on at the rated current with the judgment that the remaining amount of the lithium ion battery 23 is sufficient. First control means for turning off the light emitting diode 52 which is an auxiliary lamp.

  (5) When the value of the captured battery voltage E is less than the set value E1, the predetermined light emission of the light emitting diodes 51 and 52 is made based on the judgment that the remaining amount of the lithium ion battery 23 is insufficient. Inform by pattern. Specifically, the light emitting diode 51 is intermittently turned on, and the light emitting diode 52 is turned on only when the light emitting diode 51 is turned off. Of the operating currents of the light emitting diodes 51 and 52, at least the operating current when the light emitting diode 51 is on is set to a value smaller than the rated current in order to reduce power consumption.

  (6) Third control means for notifying the fact that the value of the captured battery voltage E is less than a predetermined value E2 (> set value E1) for a predetermined time by a predetermined light emission pattern of the light emitting diode 52.

  Next, the control executed by the drive control unit 24 will be described with reference to the flowchart of FIG.

  When the on / off switch 11 is on (YES in step 101), the drive control unit 24 detects the voltage E of the lithium ion battery 23 as the remaining amount of the lithium ion battery 23 (step 102). Subsequently, the drive control unit 24 determines whether or not the detected voltage E is equal to or higher than a set value E1 (for example, 3.4 V) (step 103). When the detection voltage E is equal to or greater than the set value E1, the drive control unit 24 determines that the detection voltage E is equal to the predetermined value E2 ( It is determined whether it is less than> set value E1) (step 104).

  When the detected voltage E is less than the predetermined value E2 (YES in Step 104), the drive control unit 24 starts the time count t based on the determination that the remaining amount of the lithium ion battery 23 is less than 50% ( Step 105). Subsequently, the drive control unit 24 turns on (lights up) the white or daylight light-emitting diode 51 that is the main light, thereby illuminating the feet around the support column 2 and the light emission of blue to green that is the auxiliary light. The diode 52 is intermittently turned on, thereby notifying that the remaining amount of the lithium ion battery 23 is half (step 106). The intermittent ON of the light-emitting diode 52 is, for example, repetition of ON for 1 second and OFF for 5 seconds, for example.

  When the on / off switch 11 is turned on, the blue to green light emitting diode 52 blinks, so that the user has the remaining amount of the built-in lithium ion battery 23 reduced to less than 50% and needs to be charged soon. Recognize accurately.

  When the time count t reaches a certain time ts, for example, 5 seconds (YES in Step 107), the drive control unit 24 clears the time count t (Step 108) and stops the light emitting diode 52 from being intermittently turned on. Thus, only turning on (lighting) of the light emitting diode 51 is continued (step 109). That is, the notification that the remaining amount of the lithium ion battery 23 has been reduced to half is finished, and the illumination at the foot with white or daylight light is continued.

  If it is determined in step 104 that the detected voltage E is not less than the predetermined value E2 (NO in step 104), the drive control unit 24 emits light based on the determination that the remaining amount of the lithium ion battery 23 is 50% or more. Without blinking the diode 52, the light emitting diode 51 is turned on (lighted) to illuminate the feet around the support column 2 (step 109).

  By the way, when the detection voltage E is less than the set value E1 in the determination in Step 103 (NO in Step 103), the drive control unit 24 determines that the remaining amount of the lithium ion battery 23 is insufficient. This is notified by a predetermined light emission pattern of the light emitting diodes 51 and 52 (step 110). That is, as shown in the time chart of FIG. 7, the drive control unit 24 intermittently turns on the light emitting diode 51 and turns on the light emitting diode 52 only when the light emitting diode 51 is off. That is, the light emitting diodes 51 and 52 are alternately turned on. For example, 5 seconds is set as the on period t1 of the light emitting diode 51, and 0.5 seconds is set as the off period t2 of the light emitting diode 51, for example.

  Since the light emitting diode 51 and the light emitting diode 52 are alternately lit, the user can accurately recognize that the remaining amount of the built-in lithium ion battery 23 is insufficient for illumination. The user who recognizes this can return home immediately, insert the charging plug of the charger into the charging terminal 13 and connect it, and charge the lithium ion battery 23 before the battery runs out. Alternatively, it is possible to take appropriate measures such as immediately turning off the on / off switch 11 to prevent the battery from running out.

  In addition, when the light emitting diode 51 is intermittently turned on, the drive control unit 24 reduces the power consumption and, in turn, extends the lithium ion battery 23, so that the operating current when the light emitting diode 51 is turned on is greater than the rated current of the light emitting diode 51. Set to a small current, for example, half of the rated current. The operating current when the light-emitting diode 52, which is an auxiliary lamp, is on may be either a rated current or a value smaller than the rated current. If the current capacity of the light-emitting diode 52 serving as the auxiliary lamp is smaller than the current capacity of the light-emitting diode 51 serving as the main lamp, the operation of the light-emitting diode 52 is performed in order to ensure the certainty of notification rather than the power consumption. Let the current be the rated current.

  When the on / off switch 11 is turned off (NO in step 101), the drive control unit 24 turns off (extinguishes) both the light-emitting diodes 51 and 52 (step 111).

  As described above, by emitting light from the illumination unit 5, it is possible to accurately inform the surrounding people of the presence of a pedestrian. If a pedestrian falls, this can be quickly noticed by the surrounding people. In particular, when the remaining amount of the lithium ion battery 23 is insufficient, the fact is notified by a change in the light emission pattern using the light emitting diode 51 itself which is the main light for illumination. It is possible to easily and quickly notice a change in lighting, that is, a shortage of the remaining amount, to a user who walks in the direction.

For 5 seconds, which is the on period t1 of the light emitting diode 51, and 0.5 seconds, which is the off period t2 of the light emitting diode 51, the user can reliably recognize the existence of the extinguishing time while making the lighting time feel as long as possible. It is a time distribution that can be made. The presence of the light does not deteriorate the lighting function. Conversely, fast flashing every 2 to 3 seconds may cause discomfort to the viewer, so such fast flashing is not employed.
Since the light emitting diode 52 having a color different from that of the normal illumination is turned on in the off period t2 of the light emitting diode 51, the alerting of the shortage of the remaining amount is enhanced as compared with the case where the light emitting diode 51 is simply turned off. In addition, since either one of the light emitting diodes 51 and 52 is always lit, the lighting operation itself continues without interruption.

  Note that the microprocessor 70 enters a sleep mode when the turn-on / off switch 11 is turned off to reduce standby power. Thereby, the power consumption of the lithium ion battery 23 is reduced as much as possible.

[About the microprocessor 70 and its peripheral parts]
In FIG. 5, the microprocessor 70 has an operable power supply voltage range of +5.5 V to +2.0 V, and a built-in A / D converter of 10 bits.

  The reference voltage Eref of the reference voltage IC 73 must be lower than the minimum value Emin of the variation range of the battery voltage E. For example, when the variation range of the battery voltage E is +4.2 V to +2.72 V, +2.5 V lower than +2.72 V that is the minimum value Emin of the variation range is determined as the reference voltage Eref.

  The maximum value Edmax of the output voltage Ed of the voltage divider composed of the series circuit of the resistors R1 and R2 must be equal to the reference voltage Eref of the reference voltage IC73. This is because the maximum value of the voltage Edmax to be analog / digital converted is the maximum digital value when it is equal to the reference voltage Eref. In order to satisfy this condition, the voltage dividing ratio by the resistors R1 and R2 is selected.

The following relationship holds between the battery voltage E, the maximum value Emax of the fluctuation range of the battery voltage E, the reference voltage Eref, and the voltage Ed.
Emax: Eref = E: Ed
Eref ・ E = Emax ・ Ed
E = (Emax / Eref) · Ed
Since the maximum value Emax is defined as + 4.5V, the ratio of the maximum value Emax to the value of the reference voltage Eref is “Emax / Eref” = + 4.5V / + 2.5V = 1.8. This 1.8 is stored in the internal memory as a constant. By using this constant, E = 1.8 · Ed.

  Therefore, the input voltage Ed from the voltage divider is analog / digital (A / D) converted based on the reference voltage Eref, and the value obtained by this analog / digital conversion is the ratio of the maximum value Emax to the value of the reference voltage Eref. By correcting with Emax / Eref = 1.8 ", the value of the battery voltage E can be captured.

  Specifically, it is assumed that the number of bits of data after digital conversion of the built-in A / D converter of the microprocessor 70 is 10 bits. In this case, the resolution of the A / D converter is 2 ^ 10 = 1024.

  Since the maximum value Emax of the battery voltage E is 4.5 V, the value in decimal notation of the digital value after A / D conversion is 1023 (d).

  The battery voltage E is proportional to the input voltage Ed to the A / D converter.

From this, the digital value Ex after A / D conversion when the battery voltage E to be found as the judgment value is 3.8 V, for example, is obtained from the following simple proportional expression:
4.5V: 1023 (d) = 3.8V: Ex
Ex = 863 (d).

  It becomes a positive real number with a value less than or equal to the decimal point from the proportional expression calculation, but rounds up to the nearest whole number by rounding up after the decimal point.

  For applications that do not require particularly high precision, calculations with floating point numbers are not required. That is, it is possible to obtain a battery voltage E that is practical even for a low-end microprocessor that is inexpensive. Further, the battery voltage E can be easily obtained from the above relational expression from the converted digital value Ex.

  As described above, by detecting the battery voltage E using the voltage divider composed of the series circuit of the microprocessor 70, the reference voltage IC 73, and the resistors R1 and R2, the lithium ion battery 23 in which the voltage fluctuation occurs is used as the operation power source. Even with a lighted cane, the voltage E of the lithium ion battery 23 can be accurately detected without consuming the power of the lithium ion battery 23 as much as possible.

  When measuring battery voltage or peripheral analog values that require high accuracy, the accuracy of the external reference voltage source affects the accuracy of the external voltage dividing resistor, and the built-in reference voltage source is used. Its accuracy is affected. Therefore, a (production) jig is constructed, several voltages corresponding to the battery voltage are given to the microprocessor, the conversion value of the A / D converter at that time is obtained with the jig, and the deviation from the correct value is corrected. The table is stored in the nonvolatile memory of the microprocessor, and correction and accuracy can be improved from this conversion table.

  On the other hand, when selecting the voltage dividing ratio by the resistors R1 and R2, assuming that the resistance values of the resistors R1 and R2 are r1 and r2, Ed = (1 / 1.8) · E is obtained as a derivative expression of E = 1.8 · Ed. . Then, r2 / (r1 + r2) = 1 / 1.8 is obtained from the condition of Ed = [r2 / (r1 + r2)] · E.

  From this, a resistance value satisfying the condition of r2 = r1 / 0.8 can be selected. In addition, since the output resistance of the signal source is required to be about 10 kΩ from the microprocessor specification, it is determined that r1 = 5.1 kΩ and r2 = 6.375 kΩ. In addition, 6.34kΩ is determined as a value close to the 6.375kΩ E-96 series resistance.

  Some microprocessors have a built-in reference voltage source. In this case, the value of the battery voltage E can be captured by using the output voltage of the built-in reference voltage source as the reference voltage Eref instead of the reference voltage IC73. In this case, it is necessary to pay attention to the accuracy of the reference voltage, but an external reference voltage circuit is not required, so that the cost can be further reduced.

[Prevention of blinking disturbance at the time of transition of the light emitting diode blinking state by the microprocessor 70]
When the remaining amount of the battery voltage E is once detected and the light emitting diodes 51 and 52 shift from the continuous lighting state to the blinking state, the battery voltage E repeatedly rises and falls slightly along with the blinking, and the fluctuation of the voltage changes. So-called chattering in which detection and non-detection of a decrease in the remaining amount are alternately repeated may be caused by the influence. In order to prevent this chattering, for example, when the value of the battery voltage E becomes less than the set value E1 continuously 10 times every 0.2 seconds, it is detected as a remaining amount decrease.

  When the voltage E of the lithium ion battery 23 is overdischarged to a predetermined value less than the set value E1, the two light emitting diodes 51 and 52 are turned on and off at the same timing. In this case, since the voltage fluctuation range at the time of switching between on and off becomes large, the detection voltage value acquired in about 0.5 seconds at the moment when the light emitting diodes 51 and 52 rise from off to on is invalidated. This prevents malfunction of overdischarge determination.

[About printed circuit boards and components]
The control circuit shown in FIG. 4 is mounted on the printed circuit board 30 shown in FIG. The printed circuit board 30 has an elongated shape extending along the axial direction of the support column 2, is inserted from the opening at the end of the support column 2, and is fixed to the upper portion of the support column 2.
The printed circuit board 30 has one surface (also referred to as a mounting surface) 30a on which components with a high mounting height are mainly disposed, and the other surface (also referred to as a solder surface) 30b on which components with a low mounting height are mainly disposed. Have Further, the printed circuit board 30 has a rectangular opening 31 at the center in the width direction. The opening 31 receives a part of the circumferential surface of the lithium ion battery 23 so as to face the other surface 30b from the one surface 30a side and holds the lithium ion battery 23.

  The component disposed on the one surface 30a is an insertion type mounting component (DIP; Dual Inline Package) in which a leg penetrates from the one surface 30a to the other surface 30b. That is, the lighting / extinguishing switch 11, the light emitting diode 12, the charging terminal 13, and the board side connector 32, which are insertion-type mounting components, are attached to a region between one end of the one surface 30a and the opening 31. An opening 36 into which a part of the charging terminal 13 is fitted is formed at the mounting position of the charging terminal 13. As the printed circuit board 30 is inserted into the support column 2 and fixed to the upper portion of the support column 2, the on / off switch 11, the light emitting diode 12, and the charging terminal 13 are formed in the support column 2 in advance. It exposes to the outer surface side of the support | pillar part 2 through the opening which is open.

  The component disposed on the other surface 30b is a surface mount component (SMD; Surface Mount Device) such as a right angle connector, a coil, or an IC chip on which a leg rests on the other surface 30b. Among these surface-mounted components, a relatively tall component is attached at a position closer to the center side in the radial direction of the support column 2 so as not to collide when placed in the cylindrical support column 2.

  The lithium ion battery 23 has a cylindrical shape that extends along the axial direction of the support column 2. Further, the lithium ion battery 23 includes a lead wire 34 led out from the end portion in the axial direction, and a battery-side connector 33 attached to the tip of the lead wire 34. With the lithium ion battery 23 set in the opening 31, the battery side connector 33 is inserted and connected to the board side connector 32.

[Modification]
In the above embodiment, the voltage monitoring of the lithium ion battery 23 of the illuminated cane has been described as an example. However, as long as the device is equipped with a battery in which voltage fluctuation occurs, not only the illuminated cane but also other devices in the same manner. It can be implemented. The battery is not limited to the lithium ion battery, and can be applied to various batteries.

  In the above-described embodiment, the push button type lighting / extinguishing switch 11 that repeatedly turns on and off each time it is pressed is used. However, a momentary type lighting / extinguishing switch 11 that conducts only when pressed may be used. In the case of a momentary type, if chattering prevention software control is performed, it is not necessary to provide a chattering prevention circuit in the switch circuit itself, and the number of parts can be reduced. In this case, the software generally eliminates or ignores the chattering period between the moment when the contact is connected and the moment when it is separated, and requires a switch pressing (ie, conduction) time of about 1 to 2 seconds. Long press operation.

  In the above embodiment, the control circuit having a microprocessor has been described. However, as shown in FIG. 9, a control circuit having no microprocessor may be used.

  In this case, the protection circuit 21 includes an undervoltage lockout circuit 65 in addition to the current fuse 61, reverse connection protection circuit 62, overvoltage protection circuit 63, and load switch circuit 64. Since the current fuse 61, the reverse connection protection circuit 62, and the overvoltage protection circuit 63 are the same as those in the above embodiment, the description thereof is omitted. The low voltage lockout circuit 65 detects an abnormality in which the input voltage is lower than the rated voltage, and detects an abnormal charging operation. When the reverse connection protection circuit 62 detects reverse connection, when the reverse connection protection circuit 62 detects an overvoltage, or when the undervoltage lockout circuit 65 detects an abnormality, the load switch circuit 64 is a subsequent charge control circuit. The current path to 22 is cut off.

  The on / off switch 11 is inserted and connected to a current path between the load cutting circuit 71 and the current fuse 72 in the drive control unit 24. In addition to the load cutting circuit 71, the current fuse 72, the main LED drive circuit 75, and the auxiliary LED drive circuit 76, the drive control unit 24 includes a reference voltage IC91, an overdischarge detection comparison circuit 92, a load switch circuit 93, and a reference voltage IC94. , A low battery level detection comparison circuit 95, a latch circuit 96, a reset IC 97, an LED blinking timing generation circuit 98, and a dimming control circuit 99. Since the load cutting circuit 71, the current fuse 72, the main LED drive circuit 75, and the auxiliary LED drive circuit 76 are the same as those in the above embodiment, the description thereof is omitted.

  The reference voltage IC91 outputs a reference voltage for overdischarge detection corresponding to a predetermined value less than the set value E1. The overdischarge detection comparison circuit 92 compares the battery voltage E with the reference voltage from the reference voltage IC 91, and determines that the lithium ion battery 23 is overdischarged when the battery voltage E is less than the reference voltage. The load switch circuit 93 cuts off power to the subsequent stage when the overdischarge detection comparison circuit 92 determines overdischarge.

  The reference voltage IC 94 outputs a reference voltage for detecting the remaining amount corresponding to the set value E1. The battery remaining amount detection comparison circuit 95 compares the battery voltage E with the reference voltage from the reference voltage IC 94, and determines that the lithium ion battery 23 is insufficient when the battery voltage E is less than the reference voltage. . The latch circuit 96 holds the determination result when the battery remaining amount decrease detection comparison circuit 95 determines that the remaining amount is insufficient. The reset IC 97 resets and initializes the contents of the latch circuit 96 at the start of energization by turning on the lighting / extinguishing switch 11 (at the beginning of lighting).

  The LED blinking timing generation circuit 98 outputs an on / off command signal for turning on / off the light emitting diodes 51, 52 when the latch circuit 96 holds the determination result of insufficient remaining amount. The dimming control circuit 99 outputs a command signal for dimming the light emission amount of the light-emitting diode 51 as the main lamp to about half when the latch circuit 96 holds the determination result that the remaining amount is insufficient.

  When the remaining amount of the battery voltage E is once detected and the light emitting diodes 51 and 52 shift from the continuous lighting state to the blinking state, the battery voltage E repeatedly rises and falls slightly along with the blinking, and the fluctuation of the voltage changes. So-called chattering in which detection and non-detection of a decrease in the remaining amount are alternately repeated may be caused by the influence. A latch circuit 96 is employed to prevent this chattering.

  In addition, the said embodiment is shown as an example and is not intending limiting the range of invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Cane body, 2 ... Support | pillar part, 3 ... Handle part, 4 ... Stone thrust part, 5 ... Illumination part, 8 ... Printed circuit board, 11 ... Light on / off switch, 12 ... Light emitting diode (light emitting body), 13 ... Charging terminal, 21 ... protection circuit, 22 ... charge control circuit, 23 ... lithium ion battery, 24 ... drive control unit, 70 ... microprocessor (calculation means), 73 ... reference voltage IC, R1, R2 ... resistor

Claims (2)

A lighted cane having a battery in which voltage fluctuation occurs as an operating power source, and having first and second light emitting diodes having different emission colors as light emitting means that operate by the power of the battery, and having an on / off switch,
A reference voltage IC that takes the battery voltage E as an input, outputs a reference voltage Eref having a value lower than the input voltage E, and outputs a weak current having an upper limit of about 2 mA ; and a voltage Ed by dividing the voltage E of the battery Voltage dividing means in which the voltage dividing ratio is set so that the maximum value Edmax of the output voltage Ed accompanying the voltage fluctuation of the battery becomes the same value as the reference voltage Eref ; and the output voltage Ed of the voltage dividing means Is converted from analog to digital based on the reference voltage Eref, and the value obtained by the analog / digital conversion is corrected by the ratio “Emax / Eref” of the maximum value Emax of the voltage fluctuation of the battery and the value of the reference voltage Eref. A voltage monitoring device including: a calculation means for capturing a value obtained by the correction as a value of the voltage E of the battery ;
A first control means for turning on the first light emitting diode to illuminate the periphery of the illuminated cane when the value of the captured voltage E is not less than a predetermined value E2 when the on / off switch is on;
When the on / off switch is turned on, if the value of the captured voltage E is not less than a set value E1 and less than the predetermined value E2, the first light emitting diode is turned on to illuminate the periphery of the illuminated cane; and Second control means for intermittently turning on the second light emitting diode for a predetermined time to notify that the remaining amount of the battery is half;
When the on / off switch is turned on, if the value of the captured voltage E is less than the set value E1, the first light emitting diode is intermittently turned on to notify that the remaining battery level is insufficient. And third control means for turning on the second light emitting diode only when the first light emitting diode is off,
A fourth control means for setting an operating current when the first light emitting diode is turned on to a current smaller than a rated current of the first light emitting diode when the first light emitting diode is intermittently turned on;
A cane with illumination . The illuminated cane has a cylindrical support, a handle provided at the upper end of the support, an illumination provided at the lower part of the support, and a stone protrusion provided at the lower end of the support,
The strut, the voltage monitoring device and the first, second, accommodates the third and fourth control means,
The illumination unit includes the first and second light emitting diodes, and transmits light of these light emitting diodes around the support column.
The illuminated cane according to claim 1.

Images