TWI336158B - Method for protecting a battery pack from a large current overdrawn condition - Google Patents

Description

1336158 IX. Description of the Invention: [Technical Field] The present invention relates to a battery charging/discharging circuit and a battery pack protection method, and more particularly to a battery capable of performing trickle precharge and/or turbulent discharge Charge/discharge circuit and protection method. The utility of the present invention can be found in a discharge/protection system for use in a portable electronic device, such as a laptop, a Personal Digital Assistant (PDA), a cell phone, and/or Any type of electronic device that can recharge a battery. [Prior Art] A rechargeable battery 'especially a clock-ion battery' must be precharged (recharged) in an exhausted state to avoid damaging the battery. When the rechargeable battery is depleted and its battery voltage becomes lower than the threshold voltage Vuv, the battery cannot be directly charged with a large charging current. Conversely, the battery needs to be charged using a pre-charge mode. In the pre-charge mode, the battery is charged with a small charging current until the battery voltage is charged to a voltage greater than the threshold voltage Vuv, and then it can be charged in the normal mode', i.e., charged with a larger charging current. For an ion battery, the threshold voltage Vuv of a cell is close to 2.4V~3] 0V, depending on the battery type and process. The precharge current is approximately 10 mA to 100 mA. However, the normal charging current can range from a few hundred milliamps to several amps, depending on the battery capacity. Fig. 1A shows a charge distribution diagram of a clock-ion rechargeable battery. When the battery voltage is higher than Vuv ’, the battery enters the Constant Current (OC) charging mode. — A large constant current is used to quickly charge the battery (the battery voltage also increases as the battery power increases). When the battery voltage increases to V〇v, which represents the overvoltage (the normal overvoltage of the internal ion battery 5 25 1336158 is about 4.2V), the battery enters the constant voltage (6), and the voltage is charged, CV). In this mode, the charger remains at voltage v〇v. When the charging current is reduced to the minimum value, for example, ο—, the charging program terminates. In the cv charging mode, the charger must accurately adjust the electrical waste to Vov (error is 5 + Λ 0. 005V), otherwise the charging current will not gradually decrease with increasing battery power. If the charge output is greater than Vov, then overcharging of the battery will occur, which can cause safety problems in the ion battery. A conventional circuit that implements pre-charging is shown in FIG. 1B. A pre-charged metal oxide semiconductor field effect transistor (Metal), which is connected in series with a resistor (Rpre), is used for pre-charging. Charge field effect transistor at the moment of pre-charging

Transistor’ FET) 16 off 'Precharged fet 12 is turned on. Therefore, the precharge current is roughly determined by the voltage difference between the charger input voltage ypACK+ and the total cell voltage VceU divided by the series resistance (Rpre) 14. When there is an AC converter (not shown) 15 and is still above the cell voltage Vce11, charging or pre-charging will start according to the initial voltage of each electric. If the voltage in any cell is below the threshold voltage Vw, the battery pack will enter pre-charge mode. On the contrary, normal charging will begin. A person skilled in the art will or include a battery monitor ic 20 in FIG. 1B, which includes monitoring the electrical 20 voltage and current of each cell (Celll, Cell2...Cell4) in the battery pack 2. Circuit. Such circuitry may include a switching network 24 for sampling each cell voltage. In order to control the operation of the pre-charged MOSFET 12, the conventional circuit 1A includes a comparator 26 which can compare a certain voltage reference source sink (ν υ ν) with each cell voltage through the switch 30. However, the circuit shown in Figure 1B has the drawback of requiring an additional power M〇SFET (also 25 'M0SFKT 12') and resistor (Rpre) 14, which adds extra cost and 6 adds printed circuit board (Printed Circuit) Board, PCB) area. In addition, in this circuit topology, a lower cell voltage results in a larger precharge current. Moreover, the precharge current decreases as the cell voltage increases, which means that it takes longer to complete the precharge. In addition, the value of the 'resistor (Rpre) 14 is usually fixed, and the maximum and minimum values of the precharge current are also generally fixed' and therefore cannot be adjusted to provide different battery pack needs. Another drawback of this circuit topology is that the battery pack 22 and MOSFETs are susceptible to damage under abnormal conditions 'e.g., the VPACK+ terminal is shorted to the VPACK-end' or the external charger is reversely applied to the VPACK+ and VPACK- terminals. In this topology, the discharge FET 18 is turned on to allow discharge or to be turned off and not to discharge. When the discharge FET 18 is turned on, if an abnormality occurs, a large current flowing from the battery pack 22 flows through the discharge FET 18 and the charge FET 16, which in turn destroys the battery pack 22 and/or MOSFETs 〇 in addition when the battery pack 22 The electronic system is removed, for example, on a rack, and the discharge FET 18 can be used to protect the battery pack 22 from abnormal conditions. However, since the discharge FET 18 is closed, when the battery pack 22 is inserted back into the electronic system, the battery pack 22 will not be able to power the electronics immediately, requiring a mechanical or electronic circuit to notify the circuit 10 to turn on the discharge FET 18. Additional mechanical methods or electronic circuitry will add to the circuit 10 noisy, micro, and/or small. Correction, Dianchi Group 22 will still be damaged due to abnormal conditions after being inserted into the electronic system. A conventional method for protecting the battery pack 22 is to turn off the discharge FET 18 to avoid generating a large current when an abnormality occurs. After the discharge FET 18 is paid for a predetermined time, for example, 30 seconds, the discharge FET 18 is turned on again. If the τ 18 is turned back on after the τ 18 is turned back on, the FET 18 is turned on the FET 18 at the high current and the battery pack is read again. Therefore, the discharge FET 18 is turned off again. Otherwise, the age of the battery 涊 1336158 = _ work in - normal discharge mode. However, if a different suspension condition exists - a period of time, a large current will continuously flow through the discharge coffee, which will eventually destroy the battery pack 22 and/or MOSFETs. ^ and /, the method is capable of turbulent pre-charging and/or 放电 discharging. The present invention mainly proposes such a circuit and method. [Summary of the Invention] In the implementation, this program provides - a variety of new 敝 to avoid large currents

Silk in an overcurrent condition. The financial method includes the steps of -opening - taking care of the signal - and if a large current overcurrent occurs, generating a ί 20 - current discharge current under the control of the control signal. Ride money to prevent the flow from circulating in the battery pack. In another embodiment, the present invention provides another method of protecting a battery pack from current overcurrent conditions. The method comprises the steps a) when a large current overcurrent condition occurs, the pay-discharge switch; b) the -switch control circuit generates a control signal, the control register has a preset table level; c) Under the control of the control signal, a turbulent discharge current is generated. The contact discharge has a critical transition and the large current flow of the Lins battery pack; d) according to the turbulent discharge current, the critical current level, and the preset maximum level detection. Whether the large current overcurrent condition still exists; e) if the large current overcurrent condition still exists 'repetition steps a) to d); and f) if the large current overcurrent condition is eliminated, the discharge switch is turned on. [Embodiment]

2A shows a trickle precharge circuit 1 in accordance with an embodiment of the present invention. In this embodiment, two MOSFETs 104 and 102 (charge FET (CHG_FET) 25 and discharge FET (DSG_FET)) are used. In this embodiment, charge FET 104 and discharge FET 8 1336158 102 are primarily described in a back-to-back series arrangement. In the pre-charge mode, the discharge FET 102 is off (non-conducting), but if the charge FET is turned on (on), the machine is still connected to the battery cell via its body (1). If the FET 104 is charged, no current flows into or out of the battery cells. 5 In addition to the two FETs, the circuit should also include a reference diode (10) 110, a two-stage t driver 106, a charge driver 108, and a reference current source (Iref) 112. Each of the charging driver 108 and the discharging driver 1〇6 includes a respective comparator. In the normal charging mode, switch (K1) 114 and switch (K2) 116 are set to position 2. In this position, a charge driving voltage CHG is driven to be equivalent to the reference voltage ίο CHGJREF, which can completely turn on the charging FET 1〇4. Therefore, the reference voltage CHG_REF is selected in accordance with the activation request of the charging FET 1〇4.

In the trickle precharge mode, switch (ΚΙ) H4 and switch (K2) 116 can be set to position 1. When the AC converter is connected, the voltage vpACK+ will rise. The charge FET 104 can be driven to the saturation region by the charge driver 1 , 8, which also means that the charge FET 15 1 〇 4 can function as a variable resistor, and a trickle charge current can flow through the charge FET 104. The charge driver 108 regulates the charge FET 104 such that the voltage Vc is equal to Vd, which is determined by the binary (D1) 110 and the reference current source (Iref) 112.

Vc is the voltage at the junction between the MOSFETs 102 and 104. Vc can be set to the negative input (-) of the comparator in charge driver 108, while Vd (determined by ^ and see 20) can be set to the positive input (1). The output signal CHG is Vd-Vc. When Vc is nearly equal to Vd, the comparator gain of charge driver 1 〇 8 is selected such that a large output signal is sufficient to drive charge FET 104 to operate in the saturation region. Thus, the 'charger driver ι 8 can compare Vc and the fixed signal Vd during trickle precharge. Under forward bias conditions, the dc current flowing through the diode (Dl) 〇 is passed through the following equation: 9 25 1336158

Iref = Al*ISl*(exp(Vdi/Vt)-l) where A1 is the junction area of the dimorphic (Dl)ll〇, IS1 is the dimorphic (w)11〇 single 兀 reverse saturation current, Vdl= Vd-Vceii is the voltage across the diode (10) no, and Vt is the diode threshold voltage. 5 The dc current of the body body in the discharge FET 102 is given by:

Ipch = A2*IS2*(exp(Vd2/Vt)-l) where A2 is the junction area of the body body' IS2 is the reverse saturation current of the body body unit, Vd2=Vc-Vcdl, is the discharge® body body body two The pressure drop at the end. (5) and IS2 are read by the selected semiconductor type. If ~ and the skin force are substantially equal, 10 then the turbulent precharge current is proportional to the reference current Iref, given by:

Ipch = A2/A1 wood (IS2/IS1) wood Iref The preferred 'miscellaneous' is not necessary for the present invention, usually because of the low turn-on voltage and high current capability, the body of the charge Fm〇2 and the discharge FET1G4 area A2 is usually At the same time, in order to save the wafer area, the diode (1) is 1) 11 〇 15 and the area A1 is small. Therefore, since A2 is much larger than A1, the small current lref (tens of micro-female) can be used to control a large current (tens to hundreds of milliamps). Figure 2B shows a choke discharge circuit 2A in accordance with an embodiment of the present invention. This embodiment is similar to the circuit 1' described in FIG. 2A except for the reference current source (Ire〇112 and diode (D1) 110 series to the discharge FET 102 terminal. During the thirst discharge period, the charge ^ 2 104 is turned off. 'The trickle discharge current flows through its body. The operation of circuit 2〇〇 is described in detail with reference to Figure 2A. ' Figure 3A shows turbulence in accordance with another embodiment of the present invention in advance in this embodiment. 'Charge FET 302 and discharge FET 304 are arranged in series face-to-face rather than back-to-back series arrangement (as shown in ® 2A). The embodiment of Figure 3A also includes a reference ice cube (10) 310, in this embodiment, a charge Driver 306 can be controlled by switch 10 1336158 (ΚΙ) 314 and switch (K2) 316. In normal charging mode, switch (ΚΙ) 314 and switch (Κ2) 316 can be again set to position 2 by δ, thus charging FET 302 The gate voltage is driven to chg_REF, and the charge FET 302 is fully turned on. In the trickle precharge mode, the discharge FET 3〇4 is turned off, and the 5 switch (K1) 314 and the switch (K2) 316 are set to the position 丨. 306 action to adjust the charging fet 302 and further The voltage vc is substantially equalized. Under forward bias conditions, the DC current of the diode (D1) 310 is given by: Iref = Al * ISl * (exp (Vdl / Vt) - l) where A1疋二^体(D1) 310 joint area, isi is di^ body (di) 310 10 unit reverse saturation current, V di=VPAK+ - Vd, is the cross-pressure of the two body (D1) 31〇, Vt is two Polar Body Threshold Voltage The DC current of the body diode in discharge FET 304 is:

Ipch=A2*IS2(exp(Vd2/Vt)-l) where A2 is the body two body connection area, IS2 is the body two body unit reverse saturation 15 current 'Vd2=VPACK+ — & 'is the discharge FET body two #体的^t D IS1 and IS2 are determined by the selected semiconductor type peak. If the suppression and Vc are forced to be the same, then the pre-charge current is given by:

Ipch = A2 / Al * (IS2 / IS1) * Iref Figure 3 is a diagram showing a choke discharge circuit 4 according to another embodiment of the present invention. The embodiment 20 is similar to the circuit 3 shown in FIG. 3A except that the reference current source (1) 312 and the 4 body (D1) 310 are coupled to the charge FET 302 terminal. The charge F lamp 302 is paid during the choke discharge, and the discharge current can flow through the body 4 of the charge FET 3〇2. The operation of circuit 400 is described in detail with reference to Figure 3A. In order to accelerate the trickle precharge process, the trickle precharge current Ipch can be quickly adjusted according to the battery voltage. The higher the battery voltage, the greater the /current precharge current by editing the reference current Iref. As is well known to those skilled in the art, the programmable I current source of Figure 4 is suitable for generating a reference current based on the battery voltage. Another trickle precharge circuit 5 is also depicted in FIG. 4. In this embodiment, charge FET 504 and discharge FET 502 are primarily described in a conventional back-to-back series arrangement. In the trickle precharge mode, the discharge FET 502 is turned off (non-conducting), but if the charge FET 504 is turned "on", current still flows through its body diode to the battery cell. If the charge FET 504 is turned off then no current flows into or out of the cell. This embodiment also includes a reference resistor R1, a discharge driver 5〇6, a charge driver 508, and a reference current source (Iref1) 512. The charge driver 5〇8 and the discharge driver 506 may include respective comparators. In the normal charging mode, switch (K1) 520 and switch (K2) 518 are set to position 1. In this position, a gate drive voltage CHG is driven to be equal to a reference voltage to fully turn on the charge fet 504. Therefore, the reference voltage CHG_REF should be selected in accordance with the startup requirements of the charging FET 504. When trickle charging is required (i.e., trickle precharge), switches K1 and K2 are connected to node 2. Thus the input to the comparator in the charging driver 5〇8 is the voltage across the sense resistor Rsens (+) and the voltage drop across R1 (generated by Irefl 512) (-). The gain of the comparator in the charging driver 508 should be designed to be large enough (for example, 80 dB) to cause the voltage drop generated by the flow of Iref1 through the resistor R1 to approximate the generated voltage of the trickle charging current Ipch flowing through the sensing resistor 1^〇5. drop. The turbulent precharge current is given by:

Ipch= Irefl ^Rl /Rsens where Irefl is a programmable reference current source. Usually Rsens is very small (e.g. 10 to 20 milliohms)' while R1 can be chosen to be in the range of 1 ohm. Therefore, the ratio of R1 to Rsens (Rl/Rsens) can be very large, so that a relatively small reference current 1153158 5 current Irefl can be used to generate a relatively large trickle precharge current Ipch. In the embodiment of Fig. 4, during the pre-charging mode, the discharge can be completely smeared by the M1. In this mode, switch (K4) 514 and switch (K3) 516 can be set to position 1 to drive discharge FET 5〇2 with discharge reference voltage DSG_REF to activate discharge FET 502. Wang Wang

10 15 20 Please continue to refer to Figure 4. In the normal discharge mode, _(10)) 516 and switch (K4) 514 can be connected to the node. . Thus, the discharge driver 5〇6 is set as a buffer and the drive discharge FET 502 is fully turned on. When in the trickle discharge mode, switch (K3) 516 and switch (K4) 514 can be connected to node 2. Since the high gain of the discharge driver 506 'because of the voltage drop caused by the flow resistance is similar to the voltage drop caused by the flow of the sense resistor Rsens. Thus, the trickle discharge current is given by: I dsg = I ref 2*R2/Rsens where Iref2 is a programmable reference current source. Usually Rsens can be very small, so the ratio of R2 to Rsens (R2/Rsens) can be very large, so a small reference current Iref2 can produce a relatively large 涓The current discharge current Idsg. Since the current direction is reversed during discharge, the voltage across the sense resistor Rsens and the voltage across the reverse have a reverse polarity. Therefore, the polarity inversion circuit 522 is used to reverse the polarity of the current flowing. In this embodiment, during trickle charging, the discharge FET 5〇2 can be fully turned on so that the forward bias of the diode between the VPACK+ and the battery voltage is eliminated. Similarly, in the choke discharge During the 'charge FET 504 can be fully turned on to eliminate the forward bias of the diode between the battery voltage and VPACK+. In the present invention, 'once the MOSFETs and the two bodies are fixed, they can still be referenced by the autumn. Current source (Ire f) 112, 312, 510, and/or 512 adjustments. A circuit topology of a programmable reference current source is depicted in Figure 5. The circuit of Figure 5 is used to generate a ratio current mirror (rati〇currerrt) Current I. Of course, in addition to the circuit shown in Figure 5, a programmable reference current source is well known in the art and can be presented in a variety of modes. Figure 6 depicts a trickle precharge and choke discharge circuit 6 In this embodiment, the charge FET 604 and the discharge FET 602 are arranged in series back-to-back or in a face-to-face arrangement as described above. In this embodiment, the digital/analog converter circuit (DAC) 616 can be Used to generate a FET drive voltage, which is described more fully below. This embodiment includes an analog/digital converter circuit (ADC) 614, a control unit 612, and a digital/analog converter circuit (10) c) 616. Control loop. The current flowing through the sense resistor (Rsens) 618 is received by the ADC 614. Next, the ADC 614 can generate a digital signal representative of the sense current and transmit the signal to the control unit 612 ° In the meantime, if the current flowing through the sense resistor (Rsens) 618 is less than a predetermined threshold, the control unit 612 can send data to the DAC 616 to increase the corresponding FET drive voltage. Conversely, the control unit 612 will send data to the DAC 616. To reduce the FET drive voltage until the sense current and the preset current are approximately equal. In normal charge or discharge mode, DAC 616 is disabled (controlled by the DAC-EN signal received by DAC 616), charge FET_ and discharge The driving voltage of the FET 6〇2 is now at a high level. Charge driver 608 drives the gate voltage of charge FET 604 to a CHG-REF value and fully turns on charge FET 604. The discharge driver 606 drives the gate voltage of the discharge FET 602 to the dsg_REF value and fully turns on the discharge FET 602. The switch (Kl) 620 is connected to the node 1 in the choke discharge mode. The discharge driver 606 is disabled (DSG-EN is low level) and has a high impedance output, and the conduction state of the discharge FET 6〇2 can be controlled by the DAC 616. Thus, discharge FET 602, sense 1336158 Rsens 618, ADC 614, and DAC 616 can form a control loop. By controlling the turn-on resistance of discharge FET 602, this embodiment is capable of adjusting the current to discharge current to a pre-δ value (which can be pre-edited to control unit 612). The turn-on resistance of the M0SFET can be adjusted by adjusting the gate drive voltage. 5 In one embodiment, if the required choke discharge current is set toltd, then the corresponding control code for the control DAC 616 can be obtained using the Successive Approximation Register (SAR). The Most Significant Bit (MSB) of the DAC is first set to a high level. If the current Isen flowing through the sense resistor (Rsens) 618 is greater than Itd, the MSB is set to a low level (i〇w). , 1〇 Otherwise the listening will be kept at a high level. Then the second highest bit is set to a high level, and if Isen is greater thanltd, the second highest bit is set to a low level (1〇w), otherwise the second most south bit 70 will be maintained at a high level. This successive approximation will continue until the lowest bit of the DAC (Significant Bit, (10)) is set. The corresponding control code can be stored in the temporary wiper (not shown) access control unit 612 for access. 15 If the 1td is a fixed value set for a given battery pack, the control is also a fixed value. Regardless of the need to ride and discharge, control unit 612 can send a programmed control code to DAC 616 ' Thus, the battery pack will be able to transmit Itd to an external load. If the 4/, IL discharge current needs to be adjusted, the above control loop can be used accordingly for = plus or f minus > control code. The charging driver (9) 8 can be caused or lost during the surface discharge. The difference is that the term stream discharge current will flow through the charge FET 604 or its body, respectively. The 'monthly charging mode' switch (K1) 62 is connected to node 2. The charging driver is offended (CHG__EN is low). The conduction state of the charging FET 6〇4 can be

Anr ¢ / 6 to control. In this mode, charge FET 604, sense __ 618, Μ and DAC 616 form a control loop. By controlling the turn-on of the charging 15 1336158, the current embodiment can adjust the trickle charging current to a predetermined value. The precharge current is usually a fixed value. In this mode, the present embodiment can generate a control code (using the SAR method described above) and store the control code in a memory. For turbulent precharge current, the value can vary from one upper limit to the lower limit. Therefore, control code 5 is also at Ctch (representing the upper limit of the turbulent precharge current) and Cra (representing the turbulent precharge current). The change between the lower limit values) allows the thirst charging current to be adjusted accordingly. In the current charging mode, the discharge driver 606 can also be enabled or disabled. The difference is that the clear current charging current will flow through the discharge jrET 602 or its body diode, respectively. > The trickle discharge mode described above can be further applied to achieve battery pack short circuit ίο / over current protection. The first embodiment of the battery pack protection is effective when the battery pack is removed from the electronic system (i.e., when the battery pack is in an idle state). Unlike the conventional method of maintaining the discharge FET 602, the first embodiment sets the discharge cis 6 〇 2 to a controllable conduction state. When the discharge FET 6〇2 is in a controlled conduction state, even if a short circuit condition occurs, for example, the VPACK+ terminal is shorted to the viewing end, a large current surge will be blocked by the opening resistance of the 15 discharge FET 602. Similarly, large current surges generated when an overcurrent condition occurs are blocked by the skin. In fact, when a short circuit/overcurrent condition occurs, the current discharge current will flow through the FET 602, and the current to be discharged can be set to a predetermined value to protect the battery pack and the MOSFET. The turbulent discharge current, e.g., should be capable of driving an external miscellaneous element of the electronic tweezers (the control unit 612 shown in the different sheds 6). When the battery pack is inserted into the electronic system, the embedded control unit detects the insertion of the battery pack and notifies the battery pack of the normal discharge mode. In this way, it is not necessary to have additional methods or electronic circuits to detect the insertion of the battery pack. This does not require additional methods or electronic circuitry to detect and notify the insertion of the battery pack. _, when the battery pack secret electronic wipes 1 - the remaining examples do not further provide battery short circuit / over current protection. Thus, the first embodiment describes a battery pack protection postal application only when the battery 16 1336158 group is removed from the electronic system. The first type is only effective when the backup battery pack is removed from the electronic system into the electronic system. In the beginning, as the steps he ==, the group is in idle (for example, 'Electricity from the electronic 彡 彡 财 · 1 财 ). Ke Wei domain ^ species = I path / overcurrent occurs. If there is no short circuit/over power~ The condition 'group will remain in the idle mode or put the Wei type. 10 15 20 way / over current condition, then step 706 immediately turns off the discharge FET coffee. The pass FET 602 can be turned off within a few microseconds. Next, in step 7〇8, if the silk has been paid for a preset time, for example, 25 seconds, unlike the traditional stalker. The field discharge FET 602 is in a controllable conductive state, and in step 71, the current is extinguished. The battery pack will operate at a predetermined time, such as ^, which has not been terminated yet, and remains in the state if it is recognized by those skilled in the art. Step 7〇8, in Figure 6, the pool management is reduced and determined. Wei Guan bought ugly enough to supervise ^ ^.疋_ has - preset time (for example 25 seconds). If a short circuit occurs H. If the preset time of the timer expires, the battery management building will know that the discharge PET 602 has been turned off for a preset period of time. In the stream discharge mode, (10) in Fig. 6 provides a gate driving voltage to the ill 602. The drive 'through the drive of the interpole drive voltage' causes the discharge FET 602 to operate in the -on state. By adjusting the gate drive voltage, the discharge resistance of the discharge is broken, so the current consumption of the flow-through electric FET 602 is adjusted accordingly. The 25 t monthly flow discharge weight can include the following sub-steps. The gate drive voltage from DAC 616 is initially slammed in step 712 under control of early control. Next, in step 714, the closed-circuit driving voltage is gradually increased. According to the characteristics of ▲, it will be easily understood by those skilled in the art that the turn-on voltage p of the discharge FET 6〇2 gradually reduces the boosting force of the gate driving voltage, so that the thirst discharge current of the flow surface is 6 〇2 will gradually increase. Each time the gate drive voltage is increased, the corresponding j-stream discharge current is detected across the resistor (Rsens) 618 and is then used to determine if the short-circuit/overcurrent condition is still present. In particular, 'in step 716', by comparing the gastric current discharge current with a predetermined current, such as '408 amps, to determine if the short circuit/overcurrent condition is still present. If the 渭 current discharge current is greater than the preset current, it can be short-circuited. Next, the system shown in Fig. 6 restarts the protection of the battery pack by the operation of step 706. If the current to be discharged is less than the preset current, in step 718, the interpole drive voltage will be compared to the preset maximum control. In fact, the gate drive voltage does not increase indefinitely and is limited to the preset maximum control level. In step 718, if the gate drive voltage reaches the preset maximum control level, it can be inferred that the short circuit/over current condition no longer exists and the battery pack will return to the idle mode or the normal discharge mode (step 702). Otherwise, the battery pack will repeat steps 714, 716, and 718 until step 716 determines that the short/over current condition exists or step 718 determines that the short/over current condition is absent and exits the choke discharge mode. The preset currents mentioned here are set by considering the power dissipation performance of the MOSFET. For the battery pack with four cells shown in Figure 6, the preset current can be set to 40 mA, so the maximum power dissipation of the discharge FET 602 is close to 68 mA, which is for the power MOSFET. A safe value. Further, the voltage at the 'VPACK+ terminal can be applied to determine whether the short/overcurrent condition exists in step 716, and the voltage at the vpacK+ terminal is detected and is, for example, 1 〇〇 millivolt. If the voltage at the edge of the 鄕 is less than the preset voltage, the short circuit/overcurrent condition still exists. Otherwise, at step 718, the inter-pole drive voltage will be compared to the preset maximum control pass. The preset voltage at the flank is set by considering the internal impedance. For the embodiment of Figure 6, the preset voltage is set to 100 volts, which is a preferred compromise between short-circuit/overcurrent conditions and the importance of noise and internal impedance of the battery. In Figure 1A, we know that during pre-charging and during constant voltage_charging, the charging current needs to be controlled. In conventional circuits, an additional pre-charge FET is required to control the pre-charge. The money-like view of the circuit towel, GV charge must rely on the charger to adjust the charging voltage to v〇v, and then the charging current will reduce the money. In the present invention, the pre-charging function can be implemented without adding additional pre-charged FETs. In addition, in order to accelerate the pre-charging process, the pre-charging current Ipch can be adjusted to be adjusted according to the battery voltage. The higher the battery voltage, the greater the precharge current obtained by programming the reference current Iref, such as the control code method described in Figures 2A, 3A and 4 or described in Figure 6. Further, as described in the various embodiments, the trickle precharge current control method can also be used to control the charging circuit according to the battery voltage. Thus, the decrement of the cv charge balance does not need to rely on the charger to accurately adjust the voltage v〇v. Therefore, the present invention provides a few embodiments that do not require an expensive, accurate voltage charger. In fact, a simple AC machine can charge the lining battery. Since the charging current is not fixed during the (7) charging period, the charging current is limited to the pre-programmed county current value depending on the battery county. Therefore, there is no overcharging condition. The charging current can be limited by the lion's second layer of overvoltage protection (through the 1336,158, the power is limited to a slightly larger current value than the actual voltage observed at the desired voltage _) (The desired voltage Vuv is precisely obtained by the secret electricity.) ^ Using the current-storage performance of the present invention, it is possible to have a better short circuit/over-voltage for the battery pack. In the prior art, the discharge FET is fully turned on to allow the discharge to be completely grounded to inhibit discharge. When the battery pack is removed from the electronic system, for example, ^ on the shelf, then the discharge FET remains in the on state to prepare to power the electronic secret when any _ 10 pool group is inserted into the electronic system ^ in this case, if : Abnormal condition 'For example, the VPACK+ terminal is shorted to the vpACK-end, then a large amount is vented from the other, so that 'the battery will be destroyed; or the discharge FET remains _ state to prevent the battery from being subjected to a short-circuit/overcurrent condition. However, when the battery pack is inserted into the system, the battery is supplied to the system. Some technical methods are needed ^^ know that the battery is turned back on and the state of the FET is turned on. This will lead to customer inconvenience and increase costs. 15 Using the invention ' § electric 峨 峨 electronic wicking is taken (four), we can set the battery pack to ship. The power supply can be used to power the built-in control unit when the battery pack is inserted into the electronic system. Then, the presence of the system__m pool of the control unit is embedded and the pool is notified to change to the normal discharge mode. With the release of current, the current is limited to the preset choke discharge.

The stream value' is assumed to be 100 mA, even if the (5) end is shorted to the WACK-end glitch will be blocked. 々丨L and 'When the battery pack is taken out of or removed from the electronic system, the battery pack of the present invention can be prepared under abnormal navigation, short circuit/overcurrent conditions. Sending a letter. Weave ' is set to a controllable conduction state at the preset off t, instead of & Wang _ as in the conventional method. 0 This battery pack will be operated on a riding towel. As the drive voltage of the open pole 20 25 gradually increases, the corresponding trickle discharge current also increases accordingly. In this process, if the corresponding turbulent discharge current is greater than the preset current, assuming 40 amps, it can be inferred that the abnormal condition persists, so the discharge FET will be turned off again and the battery pack will repeat the above operation. If the gate drive voltage is increased to a predetermined maximum control level and the corresponding choke discharge current has not reached the preset current, it can be determined that the abnormal condition has been eliminated and the battery pack can operate in the normal discharge mode. / month OIL wants electricity and / month > melon charging performance is very useful for supporting multi-battery systems. Multiple battery packs will become more common when electronic systems require shirt power and greater visibility. When multiple battery packs are simultaneously discharged, they can provide more power to the system, and because multiple battery packs in parallel will also reduce the internal impedance of the battery to increase efficiency. However, multiple battery packs_discharge have a strict premise that these pools must have the same voltage. Otherwise, even if only a small battery pack has a small voltage difference, assuming 10 millivolts 'Because the resistance of the power sink is small, assuming 2 milliohms, then the power II bus will have a large current, 5 amps. From a more ambiguous to a battery pack with a lower voltage. In fact, it is difficult for multiple battery packs to have the same voltage, because the battery pack f has a fine change in discharge power, and the battery pack has a well-defined ADC to monitor the battery voltage, and it is also determined that they have the same voltage. P's legacy of the application of the discharge ship's sage can be smudged face mask (_ with two battery packs as an example). A system has a battery pack A and a battery pack B. The voltage of the group A is higher than that of the battery pack B; the battery pack A is powered by the first stage to supply power to the system, and the voltage of the group A is gradually decreased. The discharge m of the battery_ is paid in the discharge mode or the item flow discharge mode. If we change the battery pack B to (4) charging mode, the FET can be fully turned on, and the drive charge goes to the saturation region of 1336158 and the charging FET is used as a current limiting resistor; if we set the battery pack B as a choke discharge In mode, the charge FET is fully turned on and the discharge FET is driven to its saturation region and the discharge FET is used as a current limiting resistor. Based on more safety factors, we can set the trickle charge control code Crc (representing current charge) or the current discharge control code Ctd (to be discharged) to a small current value. Therefore, the equivalent resistance of the charge FET or the discharge FET becomes larger. Since the battery pack A is discharged but the battery pack B is in the idle mode, even if the voltages at which both of them are measured are the same, the voltage of the battery pack A will actually be at the voltage of the battery pack B. Therefore, battery pack A will charge battery pack B. However, the > charge current is limited by the resistance of the charge FET (if battery pack B is set to trickle charge mode) or ίο discharge FET (if battery pack B is set to trickle discharge mode). The limited current value is determined by the control code Ctc or Cro. We also monitor the charging current through the ADC in battery pack B; as the voltage difference between battery packs a and b becomes smaller, the charging current from battery pack A to battery pack B becomes smaller and smaller. When the charging current is less than the predetermined value, 'assuming 10 mA', we can switch the battery pack B from the trickle charge mode 15 or the trickle discharge mode to the normal discharge mode. Therefore, the present invention can be pre-charged by the programmable pre-charged and/or shunt discharge circuits and methods of the present invention, which are more suitable for finer components and finer. The amount of charge in the battery pack (deep-discharged battery requires a thirst charging mode). In Figures 2A and 2B, the switches (IQ, K2 and/or K3 and K4) can be controlled by the battery monitoring IC. The programmable stream charging circuit is set to a spine precharge mode or a normal charging mode. It is further understood that the circuit architecture described in (4) can be implemented by means of separate components and/or integrated circuits. The invention is applicable to any portable electronic device (portable computer, mobile phone, ship, etc.) that uses rechargeable. 25 (five) f This is called the lang _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Jobs, threats 22 丄wo丄58 Butterfly object-to-object circuit deformation and modification [Simple diagram description] Case and ΪΓΓΪ 术 人 知道 TM TM TM TM 详细 详细 详细 详细 详细 详细 详细 详细 详细 详细 详细 详细 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐 岐The scope of the invention is defined by the following claims.

The features and advantages of the present invention will be more apparent from the following detailed description and the appended claims, wherein the same numerals represent the same parts, and wherein: Figure 1A is a typical clock ion battery charging process current , voltage diagram. FIG. 1B is a conventional battery precharge circuit. 2A is a trickle precharge circuit in accordance with an embodiment of the present invention. 2B is a choke discharge circuit in accordance with an embodiment of the present invention. 3A is a trickle precharge circuit in accordance with another embodiment of the present invention. 3B is a choke discharge circuit in accordance with another embodiment of the present invention.

4 is a precharge circuit in accordance with another embodiment of the present invention. Figure 5 is an embodiment of a programmable current source. Figure 6 is a diagram of a trickle precharge and choke discharge circuit of an embodiment. Figure 7 is a control flow diagram of battery pack short circuit/overcurrent protection in accordance with one embodiment of the present invention. [Main component symbol description] 10 : Pre-charged conventional circuit 12 : Pre-charged field effect transistor (FET) 14 : Resistor 25

Μ : Charging FET 23 1336158

Discharge FET Battery Monitor IC Battery Pack Switch Network Comparator Constant Voltage Reference Source Switch Charging Profile: Trickle Precharge Circuit: Discharge FET: Charge FET: Discharge Driver: Charge Driver: Reference β Body: Reference Current Source, 116: Switch: turbulent_discharge circuit: trickle precharge circuit: charge FET: discharge FE: T: charge driver: beta body: reference current source, 316: switch: choke discharge circuit 24 1336158 500: trickle precharge circuit 502: discharge FET 504: charge FET 506: discharge driver 5 508: charge driver 510: reference current source 512: reference current source 514, 516, 518, 520: switch 522: polarity inversion circuit 10 600: trickle precharge and Choke discharge circuit 602: discharge FET 604: charge FET 606: discharge driver 608: charge driver 15 612: control unit 614: analog-to-digital converter (ADC) 616: digital analog converter (DAC) 618: sense resistor 620: Switch 20 7 00: Control Flowchart 702~718: Step 25

Claims (1)

1336158 _ · I -- . 9I; # 2 g repair (more) is replacing 5 10, the scope of patent application: 1. A method of protecting a battery pack to avoid a current overcurrent condition, including the following. Steps: a) When When a large current overcurrent condition occurs, a discharge switch is turned off; b) a control signal is generated in a switch control circuit, the control signal has a preset maximum level, wherein the switch control circuit is powered by a charging field effect transistor Forming a discharge field effect transistor in series with the back-to-back arrangement, the charging field effect system is connected to a charging driver, and the discharge field effect transistor system is connected to a discharge driver; c) under the control signal Generating a turbulent discharge current having a critical current level and capable of preventing the large current from flowing from the battery; d) according to the turbulent discharge current, the critical current level, and the preset The maximum level detects whether the large current overcurrent condition exists; e) if the large current overcurrent condition still exists, repeating steps a) to illusion; and 〇 if the large current is overcurrent Elimination condition, the discharging switch is turned on. 2. The method of claim 1, further comprising the steps of: setting a timer; and generating the choke discharge current when the timer expires. 3. The method of claim 2, wherein the step of generating the choke discharge current further comprises setting the discharge/electric switch to a controllable conduction state under control of the control signal. 4. The method of claim 1 of the “Patent Patent Range” further includes 1 year according to the control. Month, ··? Connect. (More) Positive Replacement Page The signal adjusts the choke discharge current. *8^0- 5. The method of adjusting the current of the column discharge according to the method of the fourth paragraph of the claim 6 is further included: according to the control _ paste the Wei lion _ _ miscellaneous value; and according to the discharge to ride the electric Rugged touch current. 6. The method of claim 1, wherein if the current discharge current is at least mixed with the critical Wei scale, the occupational duty situation still exists. 7. The method of claim 1, wherein t, if the control signal is at least equal to the predetermined maximum level, the large current overcurrent condition is eliminated. 8. The method of claim 1, wherein the step (d) further comprises: a) detecting the turbulent discharge current; b) comparing the turbulent discharge current with the critical current level; c) if the 涓The flow discharge current is less than the critical current level, and the control signal is compared with the preset maximum level; d) if the control signal is less than the preset maximum level, the control signal is increased; and e) if the The flow discharge current is less than the critical current level and the control signal is less than the predetermined maximum level, then steps a) through d) are repeated. 9. The method of claim 1, wherein the step (4) further comprises: a) detecting a voltage at a positive terminal of the battery pack; b) comparing the voltage with a threshold voltage level; c) if the voltage Above the threshold voltage level, the control signal is compared with the -· - ···· * · ;99. 8: 2 0 " preset maximum level; d) if the control signal is less than the preset maximum Level, the control signal is increased; and e) if the voltage is above the threshold voltage level and the control signal is less than the predetermined maximum level, steps a) through d) are repeated. The method of claim 9, wherein the high current overcurrent condition still exists if the voltage is at most equal to the threshold voltage level.