Combination light unit and battery monitor device

• US 5,105,180 A
• Filed: 02/12/1990
• Issued: 04/14/1992
• Est. Priority Date: 02/12/1990
• Status: Expired due to Fees

• Current Assignee: Asahi Research Corporation
• Original Assignee: Asahi Research Corporation
• Inventors: Yamada, Masahiro, Yagi, Hideo
• Primary Examiner(s): Ng, Jin F.
• Assistant Examiner(s): Jackson, Jill
• Application Number:
  US07/478,548
• Time in Patent Office: 792 Days
• Field of Search: 340/636, 340/628, 352/170, 352/171, 352/172, 324/429, 324/433, 324/435, 320/48, 354/418, 354/465, 354/468, 354/473
• US Class Current: 340/636.15
• CPC Class Codes: G01R 15/04 Voltage dividers
• CPC Class Codes: G01R 19/16542 for batteries charge condition monitoring in G01R31/36
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: Y10S 320/21 State of charge of battery

Abstract

A light unit is combined with circuitry which monitors the charge level of a battery of the light unit or a video camera or camcorder connected to the light unit. With two lights of different wattages, three different constant loads can be applied while observing, in each case, LED indicators each deenergized at a certain voltage level, resulting in an accurate and reliable indication of charge level. The voltage levels are selectable in accordance with the type of battery being monitored and a bridge rectifier allows reversal of battery polarity.

Claims

1. A combination light unit and battery monitor device for use with a video camera or the like and operable by a type of battery having certain no-load output voltage and charge characteristics such that when starting at a fully charged condition and then operating with a load resistance value within a certain range its output voltage is gradually reduced to reach when in a safely discharged condition a certain safe voltage level which is a function of said load resistance value, said device comprising:

a pair of input terminal means for interconnection to a pair of terminals of said battery, light means for illumination of objects in a field of view of said camera, connecting means between said light means and said input terminal means for connecting said light means in parallel with said battery for energization therefrom, and battery charge condition indication means connected in parallel relation to said light means for monitoring the battery voltage applied from said battery to said light means, said device having first and second modes of operation, said light means including at least two light means and being arranged to operate in said first mode to provide a low level of illumination and a first predetermined value of load resistance and in said second mode to provide a higher level of illumination and a second predetermined value of load resistance lower that said first predetermined value of load resistance, said battery charge condition indicating means being arranged to operate in said first mode to indicate when the voltage across said light means has dropped below a certain voltage which is equal to said safe voltage level as determined by said first predetermined value of load resistance and in said second mode to again indicate when the voltage across said light means has dropped below a second certain voltage equal to said safe voltage level as determined by said second predetermined value of load resistance, to provide an indication of an approach of said safely discharged condition of said battery.

2. A combination light unit and battery monitor device for use with a video camera or the like and operable by a type of battery having certain no-load output voltage and charge characteristics such that when starting at a fully charged condition and then operating with a load resistance value within a certain range its output voltage is gradually reduced to reach when in a safely discharged condition a safe voltage level which is a function of said load resistance value, said device comprising:

a pair of input terminal means for interconnection to a pair of terminals of said battery, light means for illumination of objects in a field of view of said camera and providing a predetermined value of load resistance with there being a certain safe voltage level corresponding to said predetermined value of load resistance, connecting means between said light means and said input terminal means for connecting said light means in parallel with said battery for energization therefrom, and battery charge condition indicating means connected in parallel relation to said light means for monitoring the battery voltage applied from said battery to said light means, said battery charge indicating means including a first indicating light for indicating when said battery voltage has dropped to less than an intermediate voltage which is less than said no-load voltage and higher than said certain safe voltage level, a second indicating light for indicating when said battery voltage has dropped below said certain safe voltage level, and a third indicating light which is energized when said battery voltage is applied to said input terminal means.

3. A combination light unit and battery monitor device for use with a video camera or the like and operable by a type of battery having certain no-load output voltage and charge characteristics such that when starting at a fully charged condition and then operating with a load resistance value within a certain range its output voltage is gradually reduced to reach when in a safely discharged condition a safe voltage level which is a function of said load resistance value, said device comprising:

a pair of input terminal means for interconnection to a pair of terminals of said battery, light means for illumination of objects in a field of view of said camera and providing a predetermined value of load resistance with there being a certain safe voltage level corresponding to said predetermined value of load resistance, connecting means between said light means and said input terminal means for connecting said light means in parallel with said battery for energization therefrom, and battery charge condition indicating means connected in parallel relation to said light means for monitoring the battery voltage applied from said battery to said light means, said battery charge indicating means including a first indicating light for provide a first indication when said battery voltage has dropped to less than an intermediate voltage which is less than said no-load voltage and higher than said certain safe voltage level, a second indicating light for providing a second indication when said battery voltage has dropped below said certain safe voltage level, each of said indicating lights being a LED, said battery charge indicating means further including first and second differential amplifiers having output terminals connected to said first and second indicating lights and each having first and second input terminals, reference voltage means coupled to said pair of input terminal means and connected to said first input terminals of both of said differential amplifiers to supply a substantially constant reference voltage thereto, and first and second voltage divider means for controlling the voltage levels at which said first and second indicating lights provide said first and second indications, said first and second voltage divider means being coupled to said input terminal means and being respectively connected to said second input terminals of said first and second differential amplifiers.

4. A combination light unit and battery monitor device for use with a video cameras or the like and selectively operable by first and second types of batteries respectively having first and second substantially different no-load output voltages and respectively having first and second charge characteristics such that when starting at fully charged conditions and then operating with a load resistance value within a certain range the output voltages are gradually reduced to reach when in safely discharged conditions first and second substantially different safe voltage levels each of which is a function of said load resistance value, said device comprising:

a pair of input terminal means for selective interconnection to a pair of terminals of each of said first and second types of batteries, light means for illumination of objects in a field of view of said camera, connecting means between said light means and said input terminal means for selectively connecting said light means in parallel with said first and second types of battery for energization therefrom, and battery charge condition indicating means connected in parallel relation to said light means for monitoring the battery voltage applied from said battery to said light means and indicating when the battery voltage drops below a set value, and selection means for selectively setting said battery charge condition indicating means for indicating drops below said set value wherein said set value equals either said first or second safe voltage level according to whether the first or second type of battery is in use.

5. A combination light unit and battery monitor device for use with a video camera or the like and operable by a type of battery having certain no-load output voltage and charge characteristics such that when starting at a fully charged condition and then operating with a load resistance value within a certain range its output voltage is gradually reduced to reach when in a safely discharged condition a certain safe voltage level which is a function of said load resistance value, said device comprising:

a pair of input terminal means for interconnection to a pair of terminals of said battery, light means for illumination of objects in a field of view of said camera, connecting means between said light means and said input terminal means for connecting said light means in parallel with said battery for energization therefrom, battery charge condition indicating means, and connection means connecting said battery charge indicating means to said to said light means, said battery charge indicating means including circuitry requiring an operating voltage of one polarity for operation and arranged for indicating wherein the voltage across said light means has dropped below said certain safe voltage level, and said connection means including a bridge rectifier between said circuitry and said light means.

6. A battery monitor device for equipment operable by a type of battery having certain no-load output voltage and charge characteristics such that when starting at a fully charged condition and then operating with a load resistance value within a certain range its output voltage is gradually reduced to reach when in a safely discharged condition a safe voltage level which is a function of said load resistance value, said device comprising:

a pair of input terminal means for interconnection to a pair of terminals of said battery, load means for providing a predetermined value of load resistance with there being a certain safe voltage level corresponding to said predetermined value of load resistance, connecting means between said load means and said input terminal means for connecting said load means in parallel with said battery for energization therefrom, and battery charge condition indicating means connected in parallel relation to said load means for monitoring the battery voltage applied from said battery to said load means, said batter charge indicating means including a first indicating light for indicating when said battery voltage has dropped to less than an intermediate voltage which is less than said no-load voltage and higher than said certain safe voltage level, a second indicating light for indicating when said battery voltage has dropped below said certain safe voltage level, and a third indicating light which is energized when said battery voltage is applied to said input terminal means.

7. A battery monitor device for use with equipment selectively operable by first and second types of batteries respectively having first and second substantially different no-load output voltages and respectively having first and second charge characteristics such that when starting at fully charged conditions and then operating with a load resistance value within a certain range the output voltages are gradually reduced to reach when in a safely discharged conditions first and second substantially different safe voltage levels each of which is a function of said load resistance value, said device comprising:

a pair of input terminal means for selective interconnection to a pair of terminals of each of said first and second types of batteries, load means, connecting means between said load means and said input terminal means for selectively connecting said load means in parallel with said different types of battery for energization therefrom, and battery charge condition indicating means connected in parallel relation to said load means for monitoring the battery voltage applied from said battery to said load means and indicating when the battery voltage drops below a set value, and selection means for selectively setting said battery charge condition indicating means for indicating drops below said set value wherein said set value equals either said first or second safe voltage level according to whether the first or second type of battery is in use.

8. A battery monitor device for equipment operable by a type of battery having certain no-load output voltage and charge characteristics such that when starting at a fully charged condition and then operating with a load resistance value within a certain range its output voltage is gradually reduced to reach when in a safely discharged condition a certain safe voltage level which is a function of said load resistance value, said device comprising:

a pair of input terminal means for interconnection to a pair of terminals of said battery, load means, connecting means between said load means and said input terminal means for connecting said load means in parallel with said battery for energization therefrom, battery charge condition indicating means, and connection means connecting said battery charge indicating means to said to said load means, said battery charge indicating means including circuitry requiring an operating voltage of one polarity for operation and arranged for indicating when the voltage across said load means has dropped below said certain safe voltage level, and said connection means including a bridge rectifier between said circuitry and said load means.