Multi-port charging support

Abstract

The battery charger (10) has at least one charging port for a device having a rechargeable battery and a charging circuit. The charging circuit includes a DC-DC circuit, a current regulation circuit (CRC) (54), and an output voltage regulation circuit (OVA) (56), the charging port being electrically connected to an output of the CRC (54). The OVA (56) reduces the power consumed by the CRC (54) by suppressing the voltage at the input of the CRC (54) such that the CRC output voltage is sufficient to charge the rechargeable battery when the rechargeable battery is discharged. The OVA (56) increases the input voltage of the CRC (54) as the rechargeable battery is charged.

Description

[0001] Related Applications

[0002] This Patent Cooperation Treaty (PCT) international application claims the benefit under 35US119(e) of U.S. application serial number 17 / 810,070, filed on June 30, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to battery chargers and, more particularly, to battery chargers for use with a variety of hair trimmers and other devices. Background Art

[0004] Many personal care devices (e.g., hair trimmers, beard trimmers, etc.) as well as cell phones have rechargeable batteries. Some such devices require a dedicated charger port, while others only require a USB or other universal port. However, if each device had a separate charger that plugged into a line voltage outlet, the number of devices and cords would become unsightly and difficult to manage.

[0005] Thus, chargers are now available that accommodate more than one device. However, as the number of charging ports increases, the overall size of the charger also increases, which is undesirable. If multiple batteries are charged simultaneously, the power consumption (which generates heat) also increases. Therefore, there is a need for a battery charger with multiple charging ports and a compact size. There is also a need for a battery charger that controls heat dissipation.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide new and improved battery charging apparatus.

[0007] Another object is to provide a new and improved battery charger for a variety of hair trimmers and other devices.

[0008] Another object is to provide a new and improved battery charger having multiple charging ports and a compact size. Summary of the invention

[0009] The battery charger has: at least one charging port for a device having a rechargeable battery; and a charging circuit. The charging circuit includes a DC-DC circuit, a current regulation circuit (CRC), and an output voltage regulation circuit (OVA), and the charging port is electrically connected to the output of the CRC. The OVA reduces the power consumed by the CRC circuit by suppressing the voltage at the input of the CRC so that the CRC output voltage is sufficient to charge the rechargeable battery when it is discharged. The OVA circuit increases the input voltage of the CRC when the rechargeable battery is charged. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other features of the present invention and the manner in which these features are obtained will become more apparent, and the invention itself will be best understood, by referring to the following description of embodiments of the present invention taken in conjunction with the accompanying drawings, in which:

[0011] Figure 1 is a perspective view of an embodiment of a charging stand according to the present invention;

[0012] Figure 2 yes Figure 1 A perspective view of a charging stand of FIG. 1 , wherein the charger has a rechargeable battery device therein;

[0013] Figure 3 yes Figure 1 A block diagram of an output regulation circuit in a charging stand;

[0014] Figure 4 yes Figure 1 A detailed circuit diagram of a portion of the output regulation circuit of the charging support;

[0015] Figure 5 It is shown Figure 3 A diagram of simulation results of the operation of an output regulating circuit;

[0016] Figure 6 is to have and not have Figure 1 The power dissipation of the output regulation circuit is compared with the figure;

[0017] Figure 7 is a diagram showing the operation of a battery charger having an output voltage regulating circuit of the present invention; and

[0018] Figure 8 is a diagram showing the operation of a battery charger without an output voltage regulating circuit. DETAILED DESCRIPTION

[0019] Battery chargers for multiple devices can be kept small by controlling the power required to charge all devices simultaneously. The power can be controlled by adjusting the current regulating portion of the charger. To reduce the wattage (heat) dissipated by the current regulating portion of the circuit, the voltage must be reduced, or the current flowing through the circuit needs to be reduced. Reducing the current is undesirable because the current directly affects the charging time. The voltage can be reduced, but some devices require a specific voltage to be sensed to properly detect a full charge. When a full charge is detected, the device effectively disconnects the battery from the charger to avoid overcharging the battery.

[0020] like Figure 1 and 2As shown, the charging stand 10 has sockets 12, 14 and 16 for battery-powered hair trimmer / trimmer devices 18, 20 and 22. The devices 18, 20 and 22 each have an LED 24 that illuminates when the internal battery (not shown) in the device 18, 20 and 22 is fully charged. The devices also have pins (also not shown) for electrically connecting the batteries in the devices 18, 20 and 22 to spring pins 26, 28, 30 in the stand 10 for battery charging. Although the spring pins are a form of port, the port can also be in the form of hard wiring.

[0021] The cradle 10 has a pair of USB ports 32, 34 for a cell phone or the like. The cradle 10 also has an LED 36 that notifies the user that charging is enabled by emitting a blue light, and an LED 38 that notifies the user that charging is disabled by emitting a red light. A translucent cover 37 includes a company logo that is visible when either LED 36 or LED 38 is turned on.

[0022] Figure 3 A block diagram of the charging circuit is shown in FIG. Figure 3 The circuit in the embodiment is adapted by three power conditioning circuits (PAC) 51a, 51b and 51c. Figure 2 The three devices shown in FIG. 51a , 51b , and 51c are identical except that PAC51a supplies power to pogo pin 12 , PAC51b supplies power to pogo pin 14 , and PAC51c supplies power to pogo pin 16 .

[0023] exist Figure 3 In the embodiment, the AC-DC converter 50 or other suitable power source provides a DC voltage to the DC-DC converter 52 through the line 53. The DC voltage from the AC-DC converter 50 can come from the USB-C or other suitable connector. The output of the DC-DC converter 52 is transmitted to the current regulation circuit (CRC) 54. The output 55 of the CRC 54 of the PAC 51a is transmitted to the charging pin 12, the output 55 of the PAC 51b is transmitted to the pin 14, and the output 55 of the PAC 51c is transmitted to the pin 16.

[0024] Output voltage regulation circuit (OVA) 56 monitors the voltage of output 55 of CRC 54 and reduces the output voltage of DC-DC converter 52 to avoid overloading if the charge of the connected battery is low. As the connected battery charges, the output voltage returns to a higher level, as will be seen. The voltage returns to a higher level so that the sensing circuit in the device being charged is triggered to indicate charging completion through LED 24.

[0025] Figure 4 Shown in more detail Figure 3Circuit in. The DC-DC converter 52 includes capacitors 100, 102, and 104 connected between a voltage input line 53 and ground. The input line 53 is connected to the Vin pin on a DC-DC regulator 106 (e.g., AP62200WU-7). The input line 53 is also connected to a resistor 108, which is in turn connected to pin EN. The switching output SW of the regulator 106 is fed to one end of a capacitor 110 and an inductor 114, and a resistor 112 is connected in series to pin VBST. The other end of the inductor 114 is connected to parallel capacitors 116 and 118, which are in turn connected to ground, and to the input pin IN of CRC54.

[0026] CRC54 is a suitable IC, such as AP22652FDZ-7, having an input terminal IN connected to the output of DC-DC converter 52, an output terminal OUT connected to output 55, a resistor 120 connected between terminal ILIM and ground, and a capacitor 121 connected between output 55 and ground.

[0027] OVA 56 has two comparators 122 and 124. Output 55 is fed to the inverting In- terminal 125 of comparators 122 and 124 through a voltage divider including resistors 126 and 128. A fixed voltage from power line 130 is fed to the non-inverting In+ terminal 127 of comparators 122 and 124 through another voltage divider including resistors 132 and 134.

[0028] The output voltage 129 is divided by resistors 136, 138, 140 and fed to a feedback pin VFB in the regulator 106. The resistor 140 is connected to the output 125 of the DC-DC converter 52.

[0029] The output pin 131 of the comparator 124 is connected to the non-inverting input In+ terminal 127 of the comparators 122 and 124 through the resistor 142 .

[0030] In operation, each output voltage regulating circuit 56 of PAC51a, 51b, 51c monitors the voltage at the corresponding output of CRC54 through the voltage divider 126 / 128 connected to the inverting input 125 of the comparator 122 and 124. The non-inverting input 127 is connected to the reference voltage through the voltage divider 132 / 134. Both comparators 122 and 124 have open-drain outputs, so the output will either be in a high impedance (Hi-Z) state or shorted to ground. When the voltage at the inverting input 125 is less than the voltage at the non-inverting input 127, the output is in the Hi-Z state. When the situation is the opposite, the output is shorted to ground.

[0031] Figure 51 shows the voltage levels of the non-inverting input 127, the inverting input 125, and the output 129 as the inputs vary over time. The inverting input 125 indicates the voltage at the output 55. When the output of the comparator 124 is in the Hi-Z state, the resistor 142 floats and does not affect the circuit, so the voltage supplied to the non-inverting input is at a stable level, as shown in FIG. Figure 5 This is shown by the dashed line 127 (non-inverting input) in the leftmost portion 180.

[0032] When the voltage at output 55 (inverting input 125) rises to Figure 5 At point 181 in the circuit, the output 131 of comparator 124 is shorted to ground, placing resistor 142 in parallel with resistor 134 and reducing the total resistance. This in turn reduces the voltage at the non-inverting input 127, thereby Figure 5 The second input voltage 127 level is generated in region 182 in the DC-DC converter. These two voltage levels prevent the voltage ripple inherent in the DC-DC converter output from causing the comparator output to oscillate. This ripple can be Figure 5 The inverting input curve 125 is seen.

[0033] When the output 129 of the comparator 122 is in the Hi-Z state, the effective total resistance of the voltage divider 136 / 138 / 140 increases due to the resistor 138 being in series with the resistor 136. When the output of the comparator 122 is shorted to ground, the resistor 138 is removed from the circuit, which reduces the total resistance of the voltage divider 136 / 138 / 140. This change in resistance changes the voltage seen at the VFB pin of the DC-DC converter 52, which in turn causes the output voltage 129 from the DC-DC converter 52, which is fed into the CRC 54, to return to a high state, as shown in FIG. Figure 5 As shown in part 184. The device being charged recognizes that its battery is fully charged and indicates this through LED24.

[0034] The two independent comparators prevent the voltage divider 132 / 134 / 142 from affecting the voltage divider 136 / 138 / 140 because they are powered by different supplies and provide different functions. The inputs are connected in parallel so the two comparators 122, 124 transition together.

[0035] Figure 6A comparison is shown between the power dissipated by a CRC 54 without an OVA 56, embodied by line 200, and the power dissipated by a CRC 54 with an OVA 56, embodied by line 202, during battery charging. The power dissipated by the CRC 54 is defined as P = (Vin - Vout) * I. When the CRC 54 is charging a fully discharged connected battery, as shown on the left side of lines 200 and 202 (time = 0), the output 55 of the CRC 54 will start at the minimum battery voltage and increase over time as the battery is charged until the maximum battery voltage is reached. When the battery reaches its maximum voltage, circuitry within the device being charged will electrically isolate the battery from the charger to prevent further charging of the battery. Since the circuit draws much less current than the battery being charged, the voltage output of the CRC 54 will increase to a higher level. This increase, as well as other measurements, can be used by the device to detect when the device has completed charging.

[0036] Throughout the charging process, the circuit maintains a constant current level. This, combined with a fixed DC-DC output voltage at a high enough level for the device being charged, enables the increased voltage to be detected at the end of charging, which causes the CRC to dissipate excessive power in the form of heat. This heat, if not restrained, can damage components, or if the components have overheat protection, it may cause them to interrupt charging. To overcome this excessive power dissipation, OVA56 reduces the DC-DC output voltage during the initial part of the charge (when the battery voltage is lower), otherwise the power dissipation of CRC54 will be the highest. Once the battery reaches a higher voltage, CRC54 increases the output voltage of DC-DC converter 52 to the level required for the device being charged to detect the end of charging. Because the battery voltage is higher when this transition occurs, CRC54 dissipates less power than when charging initially begins. This results in lower overall power dissipation of the CRC, and therefore less heat generated, such as Figure 6 shown.

[0037] OVA56 provides voltage control for the charger. Figure 7 and Figure 8 The results of the operation of the battery charger with and without the OVA 56 are compared. The left ordinate measures voltage, the right ordinate measures current / wattage, and the abscissa measures time. Figure 7 and Figure 8 Output currents 156, 157 at the CRC output 55, output voltages 152, 153 at the CRC output 55, voltage outputs 150, 151 at the output 125 of the DC-DC converter 52, and CRC power consumptions 154, 155 are shown, respectively.

[0038] The nominal voltage of a charged lithium-ion battery is about 3.6 volts. The voltage decreases as the battery discharges and increases as the battery charges. For this purpose, it is assumed that the voltage at the CRC output 55 is close to but greater than the voltage of the battery being charged. The power consumption of the charger (which generates heat) is measured as the output voltage 154 at the DC-DC converter output 125 minus the CRC output voltage 152 multiplied by the CRC output current 156 (P = (Vin-Vout)*Iout).

[0039] Figure 7 The battery chargers measured in the test include OVA56, and Figure 8 The charger in the box does not have OVA56. Figure 7 When the voltage of the rechargeable battery in is low (time is 0-500 seconds), the voltage 152 is about 4 volts and the current 156 is about 1.5 amps. When the voltage of the rechargeable battery increases, the output voltage 55 of the CRC increases until the rechargeable battery is fully charged.

[0040] The power consumption is measured as the DC-DC output 125 minus the CRC output voltage 55 (line 152) multiplied by the CRC output current 156 (P = (Vin - Vout) * Iout). The result is line 154, which is about 0.8 Watts at about 250 minutes, about 0.6 Watts after about 2000 minutes, and about 0.4 Watts after about 4000 minutes. At about 4500 minutes, the jump in wattage in line 154 indicates when the outputs 129, 131 of the comparators 122, 124 have been transitioned to short to ground to increase the DC-DC output 125, as shown by line 150. After about 5250 minutes, the jump in volts in line 152 indicates that the device has detected that the battery has reached the maximum charging voltage, and the battery can be electrically isolated from the charging circuit, and the LED 24 can be illuminated to indicate charging is complete.

[0041] like Figure 8 As shown, the charger without OVA56 draws more power. The power consumption is measured as DC-DC output 125 ( Figure 8 155) minus the CRC output voltage 55 ( Figure 8 The power consumed is reduced by about 0.45 watts at 250 minutes, 0.2 watts at 2000 minutes, and 0.3 watts at 4000 minutes with OVA 56.

[0042] The advantages of the present invention are now obvious. Multiple rechargeable batteries can be charged by a compact charger. Heat is reduced during charging and defects are improved.

[0043] Although the principles of the present invention have been described above in conjunction with specific devices and applications, it should be understood that this description is only by way of example and does not limit the scope of the present invention.

Claims

1. A battery charger 10 comprising at least one charging port (12) for a device 18 having a rechargeable battery, the battery charger 10 also having at least one charging circuit 51A, The charging circuit 51A includes a DC-DC circuit 52, a current regulation circuit (CRC) 54, and an output voltage regulation circuit (OVA) 56. The charging port 12 is electrically connected to an output 55 of the CRC 54. in, The OVA 56 reduces the power consumed by the CRC 54 by suppressing the voltage at the input of the CRC 54 so that the CRC output voltage is sufficient to charge the rechargeable battery when the rechargeable battery is discharged. As the rechargeable battery is charged, the OVA 56 increases the input voltage of the CRC 54.

2. The battery charger 10 of claim 1, comprising a plurality of charging ports 12, 14, 16 for a plurality of devices 18, 20, 22, and a charging circuit 51A, 51B, 51C for each charging port 12, 14, 16.

3. The battery charger 10 according to claim 1, wherein: The OVA 56 includes a first open-drain comparator 122 and a second open-drain comparator 124, each of which has a non-inverting input In+127, an inverting input In-127, and an output 125. Further, the output 55 of the CRC54 is fed to the inverting In-terminal 125 of the first open-drain comparator 122 and the second open-drain comparator 124 through the first voltage divider 126, 128, The fixed voltage from the power supply 50 is fed to the non-inverting In+ terminal 127 of the first comparator and the second comparator through the second voltage divider 132, 134, The output 129 of the first comparator 122 is connected to a first resistor 138 and a second resistor 136, the first resistor 138 is also connected to ground, and the second resistor 136 is also connected to a feedback pin VFB in the DC-DC converter 52. The third resistor 140 is connected between the feedback pin VFB of the CRC and the output of the CRC.

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