HK1144036A - Switching assembly and charge detection method - Google Patents

Description

The invention relates to a circuit device and a method for detecting the availability of a charging voltage or current, which can be used, for example, to charge a battery-powered electrical appliance, preferably an electric toothbrush.

Background to the invention

Electrical battery-powered devices, such as electrical small devices such as toothbrushes or razors, are usually charged at an external charging station. During the charging process, certain functions can then be activated, such as a charging control indicator, or suppressed, such as the activation of the toothbrush. Therefore, there is a requirement to be able to detect at any time whether the device is on the charging station or not.

It is known that the charge voltage can be obtained from the charge circuit on the source side of the charge current switch via an ohmic voltage divider, which is variable depending on the charge current flow. If a charge voltage is present, the charge current circuit is therefore idle, the amount of charge voltage is maximum, a charge current flows, the charge voltage decreases. The evaluation is done by means of a microcontroller. The disadvantage here is that the ohmic voltage divider is constantly being flowed, which leads to a permanent energy consumption.

Purpose of the invention

The present invention is intended to provide a circuit device which allows charge detection without great effort.

Solution

This task shall be solved by the means and procedures as required.

A circuit arrangement is thus provided, having: an energy source capable of providing a charge voltage to charge an electric energy storage device in a charging circuit, when coupled to an energy supply, where the charge voltage is represented by an alternator, a capacitor circuit with a first capacitor element, a first valve element and the energy source, where the capacitor element is charged by the first energy source via the first valve element, when the charge voltage is negative, so that, if the charge voltage is positive, in the capacitor circuit the voltage above the first capacitor element has the same orientation as the charge voltage, and the voltage above the capacitor element and the charge energy is detected by a control device. The charge circuit is independent of whether or not it is disconnected by a DC or DC.

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If no voltage limitation measures are provided, a voltage rise of about twice the peak charge voltage can be achieved.

The charge-identification signal thus receives a voltage hub which can be twice the negative charge voltage.

Furthermore, since no complete recharging of the capacitor in the capacitor circuit is required during the charging of the energy storage device, the energy source or energy supply is not subject to any corresponding load.

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Another advantage is that the frequency of the charging part can be measured.

Beneficial continuing training in circuits may include the following features:

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In addition, there may be a control device designed to detect the voltage above the capacitor element and the energy source. The energy source may include a coil element through which energy can be coupled. Then the charging device may be designed as an inductive charging device for the energy storage. The energy storage may be an accumulator.

In the charging circuit, a third valve element may be aligned to the direction of the charging voltage, with the capacitor circuit aligned upstream of the charging current to the third valve element.

In the capacitor circuit, a first resistance element may be placed to limit the charge flow in the capacitor circuit.

The first and/or second valve elements may be located within the control device; the use of internal control functional elements may eliminate the use of external diodes, which further reduces the material requirements for the implementation of the control device.

The first valve element may be a CENER-diode element, which results in a limitation of the positive charge signalling voltage by the breakdown voltage of the CENER-diode element and a limitation of the negative charge signalling voltage by the flow voltage of the CENER-diode element.

A pulldown element may be placed parallel to the first valve element, through which the first capacitor element can be discharged if the circuit arrangement is not coupled to the power supply.

A voltage converter designed to supply the control device may be fitted, which may be used when the operating voltage of the control device is higher than the charging voltage.

For the supply of power to the control device during charging, the capacitor circuit may include a fourth valve element in series to the first capacitor and a second capacitor element parallel to the first valve element.

The invention also covers an electrically powered device, such as a razor or an electric toothbrush, with such a circuit arrangement.

A controlled switch element designed to control the charge current can be placed in the charging circuit, which can then be conveniently controlled or regulated, sparing the battery.

The invention also includes a method for detecting charge in a charging device with an energy source that can provide a charge voltage to charge an electrical energy storage device in a charging circuit when coupled to an energy supply, where the charge voltage can be represented by an alternating magnitude, whereby a first capacitor element is charged by the energy source through a first valve element when the charge voltage is negative, so that, if the charge voltage is positive, the voltage above the first capacitor element in the capacitor circuit has the same orientation as the charge voltage, and the voltage above the capacitor element and the energy source is recorded by a control device.

Preferably, a second valve element placed between a DC and the first valve element limits the voltage over the power source and the capacitor element to the sum of the DC voltage and the second valve element's throughput voltage. The voltage over the capacitor element and the power source is preferably measured by a control device. The charging voltage is preferably aligned by a third valve element. Preferably, the first capacitor element is discharged via a pulldown element placed parallel to the first valve element, if the connection arrangement is not coupled to the power supply. This can be used in a small electrical process, such as an electrical switch.

A brief description of the figures

The circuit layout is explained in detail by examples and drawings. Figure 1 a diagram of a first embodiment of a circuit assembly;Figure 2 signal paths in the first embodiment;Figure 3 signal paths in the first embodiment;Figure 4 a diagram of a second embodiment of a circuit assembly;Figure 5 a diagram of a third embodiment of a circuit assembly; andFigure 6 a diagram of a fourth embodiment of a circuit assembly.

Detailed description of the figures

The first embodiment of the circuit arrangement as shown in Fig. 1 is preferably used in an electronic circuit for an electrical small device, for example for a rechargeable electric toothbrush or for an electric razor. The energy transfer from a charging station with mains connection to the toothbrush is inductive. To this end, energy is coupled to the circuit via a charging coil L (as an energy source) which is fed through a charging circuit to an accumulator 30. The potential VL present at the charging L is a variable. A diode is also provided as a valve for the charging current, which is arranged in the direction of the charging circuit. The diode is controlled by means of DG-G as a one-way switch, so it only takes a charge from the charging reel.

A boost converter 20 is also provided to supply the microcontroller 10 with a VCC operating voltage higher than the battery voltage.

When the device is at the charging station, the idle current VI is given as the charge voltage VL at the charging coil L, i.e. when no accumulator charge current IL flows, or UA (accumulator voltage level) + UCE (transistor T1 collector emitter voltage) + UF (flow voltage over the diode DG) at the positive half-wave of the charge voltage VL, when accumulator charge current IL flows. The positive half-wave of the charge voltage then loads the circuit, so that the charge voltage VL drops.

The time course of the charge voltage VL when the charge current can flow (transistor T1 is switched on) is shown in Fig. 2 in diagram A. In the example, the charge voltage therefore oscillates between about 1.35V and -4.5V.

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The capacitor circuit consists of a series circuit of capacitor C1, resistor R1 (may be missing), first diode element D1 and the charge coil L. These elements thus form a mesh. The charge identification signal is used as the voltage UCD, which falls over the coil L and the capacitor C1 in the capacitor circuit or mesh. The charge identification signal UCD is indicative of whether the device is on the charging station or not. The charge identification signal UCD is fed to the microcontroller 10, which evaluates this.

The capacitor C1 is connected to the microcontroller 10 asymmetrically in terms of voltage via a second diode D2 at a DC VCC and the first diode D1. This is illustrated by the diagrams B of Fig. 2 and Fig. 3 in which the voltage flow UBA is plotted over the capacitor C1. The curves according to the diagrams B in Fig. 2 and Fig. 3 are almost identical to the curves according to the diagrams A. In the capacitor circuit, therefore, the charge voltages VL and UBA are oriented the same, so they have the same characteristics.

The positive half-wave of the charge voltage VL is UCD = VCC + Vf2 (Vf2 flow voltage over diode D2). During the negative half-wave of the charge voltage VL, the voltage UCD = -Vf1 (flow voltage over diode D1). The voltage pattern of the charge signal UCD is shown in Fig. 2 and Fig. 3 respectively in Diagram C.

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The charge designation voltage UCD is therefore on the order of magnitude of the VCC voltage and is thus a reliably evaluated signal (with a sufficiently large hub) for the presence of the charge voltage VL or charge current flow IL (if the charge transistor T1 is switched on) in the charge circuit.

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The charge voltage VL and thus the charge identification voltage UCD typically have a frequency in the order of 30 kHz.

The resistor R1 limits the charge flow in the capacitor circuit, i.e. the current in the port of the microcontroller 10. Parallel to the diode D1 in the capacitor circuit is a resistor R2. Resistance R2 is a pulldown resistor that ensures a complete discharge of the capacitor C1 when the charge identification signal UCD decays, when the device is no longer coupled to the charging station.

Figure 4 shows a second embodiment of the circuit arrangement in which both diodes D1 and D2 are integrated into the microcontroller 10 and can then be removed from the external circuit.

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Depending on the design of the charging coil voltage and the resistance R1, the charge detector may be relatively high, so that it hardly loads the charging part.

Furthermore, the third embodiment can be modified so that the capacitor circuit can be used as a power supply for a circuit when the device is coupled to the charging station. Figure 6 shows this variant as the fourth embodiment of a circuit arrangement. In the capacitor circuit, a rectifier diode D4 is connected, and a capacitor C2 is parallel to a Zener diode D5, which has the function of the diode D1 shown in Figures 1, 4 and 5. The capacitor C2 and the diode D4 form a rectifier in the capacitor circuit, the diode D4 is equal to the direction of current in the capacitor circuit. The Zener diode D5 limits the sum of the UCD voltage of the diode and its breakdown voltage.

The resistance R1 and the capacity C1 must be adjusted in this case so that sufficient charge can flow.

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In all embodiments, the T1 charge transistor is optional only and can therefore be omitted.

Furthermore, the charge detection described also works with a charge mechanism with full wave alignment instead of the one-way alignment by the diode DG.

The circuits described are not limited to the use in electric toothbrushes, but can also be used in other devices such as razors, household appliances or communication devices.

Claims (20)

1. A circuit assembly, showing: Other

   an energy source (L) capable of providing a charge voltage (VL) for charging an electric energy storage device (30) in a charging circuit when coupled to a power supply, where the charge voltage (VL) is represented by a variable,

   a capacitor circuit with a first capacitor element (C1), a first valve element (D1) and the power source (L),

   Other the first capacitor element (C1) is charged by the power source (L) through the first valve element (D1) when the charge voltage (VL) is negative, so that when the charge voltage (VL) is positive, the voltage (UBA) over the first capacitor element (C1) in the capacitor circuit is in the same orientation as the charge voltage (VL) signally; and the voltage (UCD) over the capacitor element (C1) and the power source (L) is detectable by a control device (10).
2. Circuit arrangement as described in claim 1, with a second valve element (D2) located between a DC (VCC) and the first valve element (D1) and limiting the voltage over the power source (L) and capacitor element (C1) to the sum of the DC (VCC) and the flow voltage (Vf2) of the second valve element (D2).
3. Circuit arrangement according to one of the previous claims, whereby, if the load voltage (VL) is negative, the voltage (UCD) over the first valve element (UCD) is limited to the flow voltage (Vf1) of the first valve element (D1).
4. A control device (10) designed to detect the voltage over the capacitor element (C1) and the power source (UCD) and having a circuit arrangement according to one of the previous claims.
5. Circuit arrangement according to one of the above claims, where the power source (L) comprises a coil element through which power can be coupled.
6. Circuit arrangement according to one of the previous claims, with a third valve element (DG) in the charging circuit to align the charge voltage (VL), where the capacitor circuit is located upstream of the third valve element (DG).
7. Circuit arrangement according to one of the previous claims, with a first resistance element (R1) located in the capacitor circuit to limit the charge flow in the capacitor circuit.
8. The control device shall be so designed that the valve is not subjected to any of the following conditions:
9. Circuit arrangement according to one of the above claims, the first valve element (D1) being a centrifugal diode.
10. Circuit arrangement according to one of the previous claims, with a pulldown element (R2) parallel to the first valve element (D1) through which the first capacitor element (C1) can be discharged when the circuit arrangement is not coupled to the power supply.
11. The control device shall be equipped with a voltage converter (20) designed to supply power to the control device (10).
12. Circuit arrangement according to one of the previous claims, with a fourth valve element (D4) in series to the first valve element (C1) and a second valve element (C2) parallel to the first valve element (D1) to supply the control device (10) of the capacitor circuit.
13. Circuit arrangement according to one of the above claims, wherein the circuit arrangement is in a small electrical device, in particular a toothbrush, and the energy storage device (30) is a battery.
14. Circuit arrangement according to one of the above claims, with a controllable switch element (T1) located in the charging circuit designed to control the charging current (IL).
15. Charge detection method in a circuit device with a power source (L) that can provide a charge voltage (VL) to charge an electrical energy storage device (30) in a charging circuit when coupled to a power supply, where the charge voltage (VL) can be represented by a variable, where a first capacitor element (C1) is charged by the energy source (L) via a first valve element (D1) when the charge voltage (VL) is negative, so that, when the charge voltage (VL) is positive, the voltage (UBA) over the first capacitor element (C1) is indicative of the same orientation as the charge voltage (VL) in the capacitor circuit, and the voltage (UCD) over the capacitor element (C1) and the energy source (L) is recorded by a control device (10).
16. The test method described in claim 15 is to use a second valve element (D2) located between a DC (VCC) and the first valve element (D1) and to limit the voltage over the power source (L) and capacitor element (C1) to the sum of the DC (VCC) voltage and the flow voltage (Vf2) of the second valve element (D2).
17. The method described in claim 15 or 16, where the voltage is measured over the capacitor element (C1) and the power source (UCD) by means of a control device (10).
18. The test shall be performed according to one of the following requirements:
19. The first condenser element (C1) is discharged via a pulldown element (R2) parallel to the first valve element (D1) when the circuit assembly is not coupled to the power supply.
20. A procedure according to one of claims 15 to 19 used in an electrical device such as an electric toothbrush.