JPH05199672A - Charger - Google Patents

Abstract

PURPOSE:To enable a charger to immediately and accurately discriminate the state of a battery, to eliminate the need of futile charging work, and to efficiently perform charging operations. CONSTITUTION:In the title charger which is constituted in such a way that the charging input of the charger is controlled by detecting the secondary-side current of a power transformer 2 connected to a charging terminal by means of a constant-current detection circuit 6 and a trickle charging current by means of a trickle charging current detection circuit 7 and by feeding back both detecting outputs of the circuits 6 and 7 to the primary side of the transformer 2, a comparator circuit 11 which compares the terminal voltage of a battery B at no-load time with a reference voltage Vref and a storage circuit 10 which stores the compared value of the circuit 11 and, when a compared value is lower than the reference voltage Vref, outputs a signal which make the charged state of the battery B to be maintained by controlling the primary side of the transformer 2 are incorporated in the input circuit of a timer for rising charging current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage battery charger which can be freely inserted and removed as a power source for television movies and various small portable electronic devices.

[0002]

2. Description of the Related Art To charge a removable lead acid battery such as a conventional video movie, as shown in FIG. 3, a rectifier 3 is connected to one side of a secondary side of a power transformer 2 and the rectifier 3 is connected to the secondary side. A storage battery B is inserted into the output side and connected to a changeover switch SW ₁ that mechanically switches from the circuit of the adapter A to the circuit of the storage battery B by moving the same, and the common terminal side of the adapter A and the storage battery B is connected. Is connected to the other secondary side of the power transformer 2 through the current detecting resistor R ₁ . A constant current detection circuit 6 and a trickle charge current detection circuit 7 (which means trickle charge of about 1 to 5% of the current when charged for 10 hours) are connected to one input side of the OR gate, and both detection circuits are connected. Resistors R ₂ and R ₃ are respectively connected between 6, 7 and the power detection transformer side of the current detection resistor R ₁ , and both switching terminals a and b of the switch SW ₁ and the current detection resistor R _{1 are connected.} Timer 8 and switch 9 between the output side of
A timer circuit (for the rising time of the charging current) consisting of the capacitor C for timing operation is connected, and the output side of the timer circuit is input to the constant current detection circuit 6. Further, the output side of the OR gate is connected to the switching circuit 1 connected to the primary side of the power transformer 2 via the voltage control circuit 5 and the drive circuit 4.

In a normal state in which the storage battery B is not inserted into the storage battery storage portion of the charger, the power supplied through the rectifier 3 is supplied to the adapter A via the terminal a of the switch SW _1.
In addition, the timer 8 stands by in a state where the switch 9 is in the "ON" state and the timer capacitor C is short-circuited and discharged, but by inserting the storage battery B and moving it. The switch SW ₁ is switched from the terminal a to the terminal b and starts charging the storage battery B. At the same time, the switch 9 of the timer circuit enters the "OFF" state (the state of not being short-circuited) to charge the capacitor C and start the timing of the initial rising time of the charging current. When the charging is started, the constant current detection circuit 6 operates, and the voltage acting on both ends of the resistor R ₁ is measured to detect the secondary side current of the power transformer 2 flowing through the resistor R _1, and at the same time, the resistor R 1 is detected. _From the set value of _3, the trickle charge current detection circuit 7 detects whether or not the charge current (current flowing through R ₁ ) has reached the current value (trickle charge detection current value) at which the mode shifts to the trickle charge voltage region mode. When the charging current reaches or exceeds the trickle charge detection current (set value) within the time determined by the timer circuit, the charging is continued. In this way, the output of either the detection circuit 6 or 7 is input to the voltage control circuit 5 via the AND gate, the voltage control signal from the voltage control circuit 5 is sent to the driver circuit 4, and the driver circuit 4 outputs the voltage control signal. The output operates the switching circuit 1. In other words, the output of the transformer 1 is constantly monitored so that the output voltage (secondary side voltage) of the power supply transformer becomes the set value by changing the number of times of switching (switching duty ratio) per hour. It controls the voltage. In this way, charging is continued while the output from the timer circuit or the output from the trickle charge current detection circuit is provided. Therefore, it is generally known that the state of the charging current changes as the charging time elapses, as shown in FIG. That is, in the charged storage battery, the charging current is constantly small even when connected to the charger, and even in the over-discharged storage battery, the charging current is a minute current until it reaches the constant current region (charging initial region).

[0004]

Therefore, as described above,
When the storage battery is charged, it is difficult to instantaneously and accurately determine whether the storage battery is a charged storage battery or an over-discharged storage battery by simply observing the state of the charging current. Therefore, the present invention intends to provide a charger which can immediately make a judgment by inserting a storage battery into the charger.

[0005]

[Means for Solving the Problems] A constant current detection circuit for detecting the secondary side current of a power transformer, which is connected to a charging terminal, that is, a charging current, and detecting that the charging current has dropped to a current value at which a trickle charge mode is entered. A trickle charge current detection circuit that feeds back the outputs from both detection circuits to the primary side of the power transformer to control the charging input. On the output side of the circuit, a comparison circuit that compares the terminal voltage when the storage battery is unloaded and the reference voltage, and the comparison value in the comparison circuit are stored, and when the comparison value is at a level equal to or lower than the reference value, trickle charging is performed. A storage circuit that outputs a signal for controlling the primary side of the power transformer to maintain the charging state regardless of the timer until the current is reached. Only composed.

[0006]

[Operation] Insert the storage battery into the charger, check whether the no-load terminal voltage of the storage battery is higher or lower than the reference voltage before starting charging, and supply constant current and voltage to the storage battery. By checking the current, it is judged whether the storage battery is charged or over-discharged, and if the no-load terminal voltage of the storage battery is higher than the reference value and the charging current is small, it is charged and the terminal voltage Is lower than the reference value and the charging current is small, it operates to indicate the state of over-discharge.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to an embodiment shown in the drawings. As shown in FIG.
A rectifier 3 is connected to one side of the secondary side of the rectifier 3, and a storage battery B is inserted and connected to the output side of the rectifier 3 and then slid and fixed to a predetermined position to mechanically fix the adapter A.
The switching switch SW ₁ adapted to switch from the circuit of B to the circuit of the storage battery B is connected, and the adapter A and the storage battery B are connected.
The common terminal side of is connected to the other secondary side of the power transformer 2 via the current detection resistor R ₁ . A constant current detection circuit 6 and a trickle charging current detection circuit 7 are connected to one input side of the OR gate, and the detection circuits 6 and 7 and the power detection transformer side of the current detection resistor R ₁ are respectively connected. The resistors R ₂ and R ₃ are interveningly connected. A circuit for comparing the no-load voltage of the storage battery, which is the most characteristic feature of the present invention, between the adapter A of the switch SW ₁ and the terminals a and b communicating with the connection terminals of the storage battery B, and a circuit for storing the comparison value are provided. To connect. That is, a storage circuit 10 (for example, a flip-flop circuit) is connected between the contact a of the switch SW ₁ and the switch 9 in the timer circuit (for charging current rise time), and the contact b of the switch SW ₁ is connected. A comparison circuit 11 that compares the no-load voltage of the storage battery B with the reference voltage Vref is connected between the storage circuit 10 and the other input side of the storage circuit 10. The storage circuit 10 is connected to the output side of the trickle charge current detection circuit 7.

In operation, when a power source is connected to the primary side of the power transformer 2 and the storage battery B is inserted into the storage battery housing, the movable contact piece of the switch SW ₁ is connected to the contact a in this state. Therefore, the storage battery B is not connected to the output side of the power transformer 2. Therefore, the terminal of the storage battery is connected to the inverting input terminal of the comparison circuit 11, while the no-load voltage of the storage battery, that is, the residual voltage of the storage battery itself is compared with the reference voltage Vref applied to the non-inverting terminal of the comparison circuit 11, Whether the no-load terminal voltage of storage battery B is higher than Vref,
Alternatively, the comparison value is compared, and the comparison value is input to the storage circuit 10 and stored therein.

Next, when the storage battery B is slid to a predetermined charging position in the storage portion of the charger, the movable contact piece of the switch SW ₁ is connected to the contact b, and the storage battery B is the secondary side of the power transformer 2. That is, it is connected to the output side of the rectifier 3 and charging is started.
The output voltage from the comparison circuit 11 stored in the storage circuit 10, that is, the no-load terminal voltage of the storage battery B is the reference voltage Vref.
The operation of the timer circuit is divided depending on whether the signal is lower or the signal indicating that the no-load terminal voltage is higher than the reference voltage Vref. That is, when the no-load terminal voltage is lower than the reference voltage Vref, it is determined that the overdischarge state is indicated. Then, in the case of over-discharging, the result is temporarily stored in the memory circuit 10, and the charging current flows regardless of the timer by locking the timer in the “ON” state.
The charge current that exceeds the trickle charge current and reaches the constant current region and then detected by the trickle charge current detection circuit 7 is
When a value equal to or less than the trickle charge current is detected, the switching circuit 1 is operated via the voltage control circuit 5 and the driver circuit 4 to control the input of the power transformer to end the charging operation.

On the other hand, when the no-load terminal voltage is higher than the reference voltage Vref in the above, the timer capacitor C is set by turning the switch 9 of the timer circuit to the "OFF" state.
Is changed from a discharged state to a charged state, and it is determined whether the storage battery B should be charged until the capacitor C is completely charged, that is, within the charging current rising time.
However, even if the no-load terminal voltage of the storage battery is higher than the reference voltage Vref, it may be because the state of charge is saturated, or there is still enough power to operate the device, and the battery can be charged. It is not possible to judge whether or not it shows such a state. Therefore, by passing the charging current to the storage battery B, the charging current is always small when the charging state is saturated. Stop the operation. However, when the charging current detected by the trickle charging current detection circuit 7 is larger than the trickle charging current,
In this case, the memory circuit is reset based on the result, and the "ON" state of the timer circuit is unlocked to execute the normal charging operation. Then, the charging ends when the charging current reaches the constant current and then becomes lower than the trickle charging current again.

[0011]

As described above, according to the present invention, by inserting the storage battery as described above, first, the no-load terminal voltage of the storage battery is detected, and then the charging current is checked by passing a current through the storage battery, whereby the battery is fully charged. Can immediately make an accurate judgment as to whether or not there is still power remaining or is in an over-discharged state, do not perform unnecessary charging operation on a charged storage battery, or charge a partially discharged battery. Even when the operation is performed or the electric power is discharged and the electric power is exhausted, it can be charged within the required charging time, so that the charging operation can be efficiently performed without waste.

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention.

FIG. 2 is a flowchart of the charging operation of the above.

FIG. 3 is a block diagram of a conventional example.

FIG. 4 is a time-charging current characteristic diagram of FIG. 3.

[Explanation of symbols]

1 Switching Circuit 2 Power Transformer 6 Constant Current Detection Circuit 7 Trickle Charge Current Detection Circuit 8 Timer 9 Switch 10 Storage Circuit 11 Comparison Circuit B Storage Battery SW ₁ Switch Vref Reference Voltage

Claims (1)

[Claims] 1. A constant current detection circuit for detecting a secondary side current of a power supply transformer communicating with a charging terminal and a trickle charge current detection circuit for detecting a trickle charge current. Outputs from both detection circuits are supplied to the power supply transformer. In the charger that controls the charging input by feeding back to the primary side, the terminal voltage and the reference voltage when the storage battery is unloaded are connected to the input circuit of the charging rising timer and the output side of the trickle charging current detection circuit. And a comparison circuit for comparing the values stored in the comparison circuit, and when the comparison value is at a level lower than a reference value, controls the primary input of the power transformer regardless of the timer until the trickle charge current is reached. And a storage circuit that outputs a signal for maintaining the proper charge state.