Another charger is assembled according to the circuit of a key current stabilizer with a unit for monitoring the achieved voltage on the battery to ensure that it is turned off at the end of charging. To control the key transistor, a widely used specialized microcircuit TL494 (KIA491, K1114UE4) is used. The device provides regulation of the charge current within 1 ... 6 A (10 A max) and output voltage 2 ... 20 V.
The key transistor VT1, diode VD5 and power diodes VD1 - VD4 through mica spacers must be installed on a common radiator with an area of 200 ... 400 cm2. The most important element in the circuit is inductor L1. The efficiency of the circuit depends on the quality of its manufacture. As a core, you can use a pulse transformer from a 3USTST TV power supply or similar. It is very important that the magnetic core has a slot gap of approximately 0.5 ... 1.5 mm to prevent saturation at high currents. The number of turns depends on the specific magnetic circuit and can be in the range of 15 ... 100 turns of PEV-2 2.0 mm wire. If the number of turns is excessive, then a soft whistling sound will be heard when the circuit operates at rated load. As a rule, the whistling sound occurs only at medium currents, and with a heavy load, the inductance of the inductor due to the magnetization of the core drops and the whistling stops. If the whistling sound stops at low currents and with a further increase in the load current, the output transistor begins to heat up sharply, then the area of the magnetic core is insufficient to operate at the selected generation frequency - it is necessary to increase the operating frequency of the microcircuit by selecting resistor R4 or capacitor C3 or install a larger inductor. If there is no power transistor of the p-n-p structure in the circuit, you can use powerful transistors of the n-p-n structure, as shown in the figure.
As a diode VD5 in front of inductor L1, it is advisable to use any available diodes with a Schottky barrier, rated for a current of at least 10A and a voltage of 50V; in extreme cases, you can use mid-frequency diodes KD213, KD2997 or similar imported ones. For the rectifier, you can use any powerful diodes with a current of 10A or a diode bridge, for example KBPC3506, MP3508 or the like. It is advisable to adjust the shunt resistance in the circuit to the required value. The range of adjustment of the output current depends on the ratio of the resistances of the resistors in the output circuit 15 of the microcircuit. In the lower position of the current control variable resistor slider in the diagram, the voltage at pin 15 of the microcircuit must coincide with the voltage on the shunt when the maximum current flows through it. The variable current control resistor R3 can be set with any nominal resistance, but you will need to select a fixed resistor R2 adjacent to it to obtain the required voltage at pin 15 of the microcircuit.
The variable output voltage adjustment resistor R9 can also have a wide range of nominal resistance 2 ... 100 kOhm. By selecting the resistance of resistor R10, the upper limit of the output voltage is set. The lower limit is determined by the ratio of the resistances of resistors R6 and R7, but it is undesirable to set it less than 1 V.
The microcircuit is installed on a small printed circuit board 45 x 40 mm, the remaining elements of the circuit are installed on the base of the device and the radiator.
The wiring diagram for connecting the printed circuit board is shown in the figure below.
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The circuit used a rewound TS180 power transformer, but depending on the magnitude of the required output voltages and current, the power of the transformer can be changed. If an output voltage of 15 V and a current of 6 A is sufficient, then a power transformer with a power of 100 W is sufficient. The radiator area can also be reduced to 100...200 cm2. The device can be used as a laboratory power supply with adjustable output current limitation. If the elements are in good working order, the circuit starts working immediately and only requires adjustment.
Source: http://shemotechnik.ru
Scheme:
The charger is assembled according to the circuit of a key current stabilizer with a unit for monitoring the achieved voltage on the battery to ensure that it is turned off at the end of charging. To control the key transistor, a widely used specialized microcircuit TL494 (KIA491, K1114UE4) is used. The device provides regulation of the charge current within 1 ... 6 A (10 A max) and output voltage 2 ... 20 V.
The key transistor VT1, diode VD5 and power diodes VD1 - VD4 through mica spacers must be installed on a common radiator with an area of 200 ... 400 cm2. The most important element in the circuit is inductor L1. The efficiency of the circuit depends on the quality of its manufacture. As a core, you can use a pulse transformer from a 3USTST TV power supply or similar. It is very important that the magnetic core has a slot gap of approximately 0.5 ... 1.5 mm to prevent saturation at high currents. The number of turns depends on the specific magnetic circuit and can be in the range of 15 ... 100 turns of PEV-2 2.0 mm wire. If the number of turns is excessive, then a soft whistling sound will be heard when the circuit operates at rated load. As a rule, the whistling sound occurs only at medium currents, and with a heavy load, the inductance of the inductor due to the magnetization of the core drops and the whistling stops. If the whistling sound stops at low currents and with a further increase in the load current, the output transistor begins to heat up sharply, then the area of the magnetic core is insufficient to operate at the selected generation frequency - it is necessary to increase the operating frequency of the microcircuit by selecting resistor R4 or capacitor C3 or install a larger inductor. If there is no power transistor of the p-n-p structure in the circuit, you can use powerful transistors of the n-p-n structure, as shown in the figure.
Details:
As a diode VD5 in front of inductor L1, it is advisable to use any available diodes with a Schottky barrier, rated for a current of at least 10A and a voltage of 50V; in extreme cases, you can use mid-frequency diodes KD213, KD2997 or similar imported ones. For the rectifier, you can use any powerful diodes with a current of 10A or a diode bridge, for example KBPC3506, MP3508 or the like. It is advisable to adjust the shunt resistance in the circuit to the required value. The range of adjustment of the output current depends on the ratio of the resistances of the resistors in the output circuit 15 of the microcircuit. In the lower position of the current control variable resistor slider in the diagram, the voltage at pin 15 of the microcircuit must coincide with the voltage on the shunt when the maximum current flows through it. The variable current control resistor R3 can be set with any nominal resistance, but you will need to select a fixed resistor R2 adjacent to it to obtain the required voltage at pin 15 of the microcircuit.
The variable output voltage adjustment resistor R9 can also have a wide range of nominal resistance 2 ... 100 kOhm. By selecting the resistance of resistor R10, the upper limit of the output voltage is set. The lower limit is determined by the ratio of the resistances of resistors R6 and R7, but it is undesirable to set it less than 1 V.
The microcircuit is installed on a small printed circuit board 45 x 40 mm, the remaining elements of the circuit are installed on the base of the device and the radiator.
Printed circuit board:
Wiring diagram:
The circuit used a rewound TS180 power transformer, but depending on the magnitude of the required output voltages and current, the power of the transformer can be changed. If an output voltage of 15 V and a current of 6 A is sufficient, then a power transformer with a power of 100 W is sufficient. The radiator area can also be reduced to 100...200 cm2. The device can be used as a laboratory power supply with adjustable output current limitation. If the elements are in good working order, the circuit starts working immediately and only requires adjustment.
Another charger is assembled according to the circuit of a key current stabilizer with a unit for monitoring the achieved voltage on the battery to ensure that it is turned off at the end of charging. To control the key transistor, a widely used specialized microcircuit TL494 (KIA491, K1114UE4) is used. The device provides regulation of the charge current within 1 ... 6 A (10 A max) and output voltage 2 ... 20 V.
Car battery for TL494" title="Charger for car battery for TL494"/>!}
The key transistor VT1, diode VD5 and power diodes VD1 - VD4 through mica spacers must be installed on a common radiator with an area of 200 ... 400 cm2. The most important element in the circuit is inductor L1. The efficiency of the circuit depends on the quality of its manufacture. As a core, you can use a pulse transformer from a 3USTST TV power supply or similar. It is very important that the magnetic core has a slot gap of approximately 0.5 ... 1.5 mm to prevent saturation at high currents. The number of turns depends on the specific magnetic circuit and can be in the range of 15 ... 100 turns of PEV-2 2.0 mm wire. If the number of turns is excessive, then a soft whistling sound will be heard when the circuit operates at rated load. As a rule, the whistling sound occurs only at medium currents, and with a heavy load, the inductance of the inductor due to the magnetization of the core drops and the whistling stops. If the whistling sound stops at low currents and with a further increase in the load current, the output transistor begins to heat up sharply, then the area of the magnetic core is insufficient to operate at the selected generation frequency - it is necessary to increase the operating frequency of the microcircuit by selecting resistor R4 or capacitor C3 or install a larger inductor. If there is no power transistor of the p-n-p structure in the circuit, you can use powerful transistors of the n-p-n structure, as shown in the figure.
As a diode VD5 in front of inductor L1, it is advisable to use any available diodes with a Schottky barrier, rated for a current of at least 10A and a voltage of 50V; in extreme cases, you can use mid-frequency diodes KD213, KD2997 or similar imported ones. For the rectifier, you can use any powerful diodes with a current of 10A or a diode bridge, for example KBPC3506, MP3508 or the like. It is advisable to adjust the shunt resistance in the circuit to the required value. The range of adjustment of the output current depends on the ratio of the resistances of the resistors in the output circuit 15 of the microcircuit. In the lower position of the current control variable resistor slider in the diagram, the voltage at pin 15 of the microcircuit must coincide with the voltage on the shunt when the maximum current flows through it. The variable current control resistor R3 can be set with any nominal resistance, but you will need to select a fixed resistor R2 adjacent to it to obtain the required voltage at pin 15 of the microcircuit.
The variable output voltage adjustment resistor R9 can also have a wide range of nominal resistance 2 ... 100 kOhm. By selecting the resistance of resistor R10, the upper limit of the output voltage is set. The lower limit is determined by the ratio of the resistances of resistors R6 and R7, but it is undesirable to set it less than 1 V.
The microcircuit is installed on a small printed circuit board 45 x 40 mm, the remaining elements of the circuit are installed on the base of the device and the radiator.
The wiring diagram for connecting the printed circuit board is shown in the figure below.
The circuit used a rewound TS180 power transformer, but depending on the magnitude of the required output voltages and current, the power of the transformer can be changed. If an output voltage of 15 V and a current of 6 A is sufficient, then a power transformer with a power of 100 W is sufficient. The radiator area can also be reduced to 100...200 cm2. The device can be used as a laboratory power supply with adjustable output current limitation. If the elements are in good working order, the circuit starts working immediately and only requires adjustment.
CHARGING DEVICE FOR CAR BATTERIES
Another charger assembled according to the circuit of a key current stabilizer with a unit for monitoring the achieved voltage on the battery to ensure that it is turned off at the end of charging. A widely used specialized microcircuit is used to control the key transistor TL494 (KIA494, KA7500B, K1114UE4). The device provides charge current regulation within 1 ... 6 A (10A max) and output voltage 2 ... 20 V.
Key transistor VT1, diode VD5 and power diodes VD1 - VD4 through mica spacers must be installed on a common radiator with an area of 200 ... 400 cm2. The most important element in the circuit is the inductor L1. The efficiency of the circuit depends on the quality of its manufacture. The requirements for its manufacture are described in As a core, you can use a pulse transformer from the power supply of 3USTST TVs or a similar one. It is very important that the magnetic core has a slot gap of approximately 0.2 ... 1, 0
mm to prevent saturation at high currents. The number of turns depends on the specific magnetic circuit and can be in the range of 15 ... 100 turns of PEV-2 2.0 mm wire. If the number of turns is excessive, then a soft whistling sound will be heard when the circuit operates at rated load. As a rule, the whistling sound occurs only at medium currents, and with a heavy load, the inductance of the inductor due to the magnetization of the core drops and the whistling stops. If the whistling sound stops at low currents and with a further increase in the load current the output transistor begins to heat up sharply, then the area of the magnetic circuit core is insufficient to operate at the selected generation frequency - it is necessary to increase the operating frequency of the microcircuit selection of resistor R4 or capacitor C3 or install a larger choke. In the absence of a power transistor structure p-n-p in the circuit you can use powerful transistors of the structure n-p-n , as it shown on the picture.
