bq2007 Fast-Charge IC - Features ➤ Fast charging and conditioning of NiCd and NiMH batteries - Precise charging independent of battery pack number of cells - Discharge-before-charge on demand - Pulse trickle charge conditioning - Battery undervoltage and overvoltage protection ➤ Built-in 10-step voltage-based charge status monitoring - Charge status display options include seven-segment monotonic bargraph and fully decoded BCD digit Display interface options for direct drive of LCD or LED segments Charger state status indicators for pending, discharge, charge, completion, and fault Pin Connections SEGC/MSEL SEGB SEGA LED1 LED2 INH COM ALARM TM VSEL FAST DCMD 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 24-Pin Narrow DIP or SOIC PN200701.eps SEGD/DSEL1 SEGE/DSEL2 SEGF/MULT SEGG/QDSEL MOD VCC VSS DIS TS BAT SNS TCO Audible alarm for charge completion and fault conditions ➤ Charge control flexibility - Fast or Standard speed charging - Top-off mode for NiMH Charge rates from C 8 to 2C (30 minutes to 8 hours) ➤ Charge termination by: - Negative delta voltage (-∆V) Peak voltage detect (PVD) Maximum voltage Maximum time Maximum temperature ➤ High-efficiency switch-mode design - Ideal for small heat-sensitive enclosures General Description The bq2007 is a highly integrated monolithic CMOS IC designed to provide intelligent battery charging and charge status monitoring for standalone charge systems. The bq2007 provides a wide variety of charge status display formats. The bq2007 internal charge status monitor supports up to a seven-segment bargraph or a single BCD digit display. The bargraph display indicates up to seven monotonic steps, whereas the BCD digit counts in ten steps of 10% increments. The bq2007 output drivers can direct-drive either an LCD or LED display. Charge action begins either by application of the charging supply or by replacement of the battery pack. For safety, charging is inhibited until battery temperature and voltage are within configured limits. ➤ 24-pin, 300-mil SOIC or DIP Pin Names SEGC/ MSEL Display output segment C/ driver mode select SEGB Display output segment B SEGA Display output segment A LED1 Charge status output 1 LED2 Charge status output 2 INH Charge inhibit input COM Common LED/LCD output ALARM Audio alarm output TM Timer mode select VSEL Voltage termination select FAST Fast charge rate select DCMD Discharge command TCO Temperature cutoff 9/96 B 1 SNS Sense resistor input BAT Battery voltage TS Temperature sense DIS Discharge control VSS System ground VCC 5.0V ± 10% power MOD Modulation control SEGG/ QDSEL Display output segment G/ charge status display select SEGF/ MULT Display output segment F/ multi-cell pack select SEGE/ DSEL2 Display output segment E/ display select 2 SEGD/ DSEL1 Display output segment D/ display select 1 bq2007 The bq2007 indicates charge state status with an audio alarm output option and two dedicated output pins with programmable display options. The DSEL1–2 inputs can select one of the three display modes for the LED1–2 outputs. The acceptable battery temperature range is set by an internal low-temperature threshold and an external high-temperature cutoff threshold. The absolute temperature is monitored as a voltage on the TS pin with the external thermistor network shown in Figure 2. Charger status is indicated for: The bq2007 provides for undervoltage battery protection from high-current charging if the battery voltage is less than the normal end-of-discharge value. In the case of a deeply discharged battery, the bq2007 enters the charge-pending state and attempts trickle-current conditioning of the battery until the voltage increases. Should the battery voltage fail to increase above the discharge value during the undervoltage time-out period, a fault condition is indicated. n Charge pending n Charge in progress n Charge complete n Fault condition Pin Descriptions Discharge-before-charge may be selected to automatically discharge the battery pack on battery insertion or with a push-button switch. Discharge-before-charge on demand provides conditioning services that are useful to correct or prevent the NiCd voltage depression, or “memory” effect, and also provide a zero capacity reference for accurate capacity monitoring. SEGA–G State-of-charge monitoring outputs. QDSEL input selects the bargraph or BCD digit display mode. See Table 3. MSEL After prequalification and any required dischargebefore-charge operations, charge action begins until one of the full-charge termination conditions is detected. The bq2007 terminates charging by any of the following methods: n Negative delta voltage (-∆V) n Peak voltage detect (PVD) n Maximum absolute temperature n Maximum battery voltage n Maximum charge time-out Display output segments A–G Display driver mode select Soft-programmed input selects LED or LCD driver configuration at initialization. When MSEL is pulled up to VCC, outputs SEGA–G are LED interface levels; when MSEL is pulled down to VSS, outputs SEGA–G are LCD levels. DSEL1– DSEL2 Display mode select 1–2 Soft-programmed inputs control the LED1—2 charger status display modes at initialization. See Table 2. MULT The bq2007 may be programmed for negative delta voltage (-∆V) or peak voltage detect (PVD) charge termination algorithms. The VSEL input pin selects -∆V or PVD termination to match the charge rate and battery characteristics. Fixed-cell pack select Soft-programmed input is pulled up to VCC when charging multi-cell packs and is pulled down to VSS for charging packs with a fixed number of cells. QDSEL To provide maximum safety for battery and system, charging terminates based on maximum temperature cutoff (TCO), maximum cutoff voltage (MCV), and maximum time-out (MTO). The TCO threshold is the maximum battery temperature limit for charging. TCO terminates charge action when the temperature sense input voltage on the TS pin drops below the TCO pin voltage threshold. MCV provides battery overvoltage protection by detecting when the battery cell voltage (VCELL = VBAT - VSNS) exceeds the VMCV value and terminates fast charge, standard charge, or top-off charge. The maximum time-out (MTO) termination occurs when the charger safety timer has completed during the active charge state. State-of-charge display select The QDSEL input controls the SEGA–G state-of-charge display modes. See Table 3. LED1– LED2 Charger status outputs 1–2 Charger status output drivers for direct drive of LED displays. Display modes are selected by the DSEL input. See Table 2. INH Charge inhibit input When low, the bq2007 suspends all charge actions, drives all outputs to high impedance, and assumes a low-power operational state. When transitioning from low to high, a charge cycle is initiated. See page 10 for details. 2 bq2007 COM Common LCD/LED output TS Input referenced to SNS for battery temperature monitoring negative temperature coefficient (NTC) thermistor. Common output for LCD/LED display SEGA—G. Output is high-impedance during initialization to allow reading of soft-programmed inputs DSEL1, DSEL2, MSEL, MULT, and QDSEL. ALARM DIS VSEL Timer mode select VSS Ground TM is a three-level input that controls the settings for charge control functions. See Table 5. VCC VCC supply input MOD Current-switching control output Voltage termination select Push/pull output that controls the charging current to the battery. MOD switches high to enable current flow and low to inhibit current flow. This input switches the voltage detect sensitivity. See Table 5. FAST Fast charge rate select Functional Description The FAST input switches between Fast and Standard charge rates. See Table 4. DCMD Figure 1 illustrates charge control and display status during a bq2007 charge cycle. Table 1 summarizes the bq2007 operational features. The charge action states and control outputs are given for possible input conditions. Discharge command The DCMD input controls the dischargebefore-charge function. A negative-going pulse initiates a discharge action. If DCMD is connected to VSS, automatic dischargebefore-charge is enabled. See Figure 3. TCO Charge Action Control The bq2007 charge action is controlled by input pins DCMD, VSEL, FAST, and TM. When charge action is initiated, the bq2007 enters the charge-pending state, checks for acceptable battery voltage and temperature, and performs any required discharge-before-charge operations. DCMD controls the discharge-before-charge function, and VSEL, FAST, and TM select the charger configuration. See Tables 4 and 5. Temperature cut-off threshold input Minimum allowable battery temperaturesensor voltage. If the potential between TS and SNS is less than the voltage at the TCO input, then any fast charging or top-off charging is terminated. SNS Sense resistor input During charging, the bq2007 continuously tests for charge termination conditions: negative delta voltage, peak voltage detection, maximum time-out, battery over-voltage, and high-temperature cutoff. When the charge state is terminated, a trickle charge continues to compensate for self-discharge and maintain the fully charged condition. SNS controls the switching of MOD output based on an external sense resistor. This provides the lower reference potential for the BAT pin and the TS pin. BAT Discharge control DIS is a push-pull output that controls an external transistor to discharge the battery before charging. Audio output Audio alarm output. TM Temperature sense input Battery voltage input Battery voltage sense input referenced to SNS for the battery pack being charged. This resistor divider network is connected between the positive and the negative terminals of the battery. See Figure 1. Charge Status Indication Table 2 summarizes the bq2007 charge status display indications. The charge status indicators include the DIS output, which can be used to indicate the discharge state, the audio ALARM output, which indicates charge completion and fault conditions, and the dedicated status outputs, LED1 and LED2. 3 bq2007 Charge Pending Discharge (Pulse-Trickle) (Optional) Top-Off Fast Charging Pulse-Trickle (Optional) DIS MOD or MOD 260 s Note 2080 s 260 s Note (Switching Configuration) (External Regulation) 2080 s Mode 1, LED2 Status Output 260 s 260 s Mode 1, LED1 Status Output Mode 2, LED2 Status Output Mode 2, LED1 Status Output Mode 3, LED2 Status Output Mode 3, LED1 Status Output Battery discharged to VEDV or battery within temperature/voltage limits. (Discharge-before-charge not qualified by temperature.) Low-voltage fault: Battery voltage less than VEDV for under-voltage time-out. Charge initiated. Battery outside temperature/voltage limits. Note: See Table 4 for pulse-trickle period. TD200701.eps Figure 1. Example Charging Action Events 4 bq2007 Outputs LED 1–2 have three display modes that are selected at initialization by the input pins DSEL1 and DSEL2. The DSEL1 and DSEL2 input pins, when pulled down to V SS , are intended for implementation of a simple two-LED system. LED2 indicates the precharge status (i.e., charge pending and discharge) and LED1 indicates the charge status (i.e., charging and completion). DSEL1 pulled up to VCC and DSEL2 pulled down to VSS mode is for implementation of a single tri-color LED such that discharge, charging, and completion each have a unique color. DSEL1 pulled down to VSS and DSEL2 pulled up to VCC allows for fault status information to be displayed. Charge Status Monitoring The bq2007 charge status monitor may display the battery voltage or charge safety timer as a percentage of the full-charged condition. These options are selected with the MULT soft-programmed input pin. When MULT is pulled down to VSS, the battery charge status is displayed as a percentage of the battery voltage, and the single-cell battery voltage at the BAT pin is compared with internal charge voltage reference thresholds. When VBAT is greater than the internal thresholds of V20, V40, V60, or V80, the respective 20%, 40%, 60%, or 80% display outputs are activated. The b a t t er y v olt a g e d ir ec t ly in d ic a t es 2 0 % ch a r g e increments, while the 10% charge increments use a timer that is a function of the charge safety timer. Audio Output Alarm The bq2007 audio alarm output generates an audio tone to indicate a charge completion or fault condition. The audio alarm output is a symmetrical duty-cycle AC signal that is compatible with standard piezoelectric alarm elements. A valid battery insertion is indicated by a single high-tone beep of 1 2-second typical duration. The charge completion and fault conditions are indicated by a 9.5- to 15-second high-tone sequence of 1 2-second typical duration at a 2-second typical repetition rate. When MULT is pulled down to VSS and when VBAT exceeds V20 during charging, the 20% charge indication is activated and the timer begins counting for a period equal to 1 64 to 1 32 of the charge safety time-out period. When the timer count is completed, the 30% charge indication is activated. Should VBAT exceed V40 prior to the timer count completion, the charge status monitor activates the 30% and 40% indications. This technique Table 1. bq2007 Operational Summary Charge Action State Battery absent Charge initiation Discharge-beforecharge Charge pending Conditions VCC applied and VCELL ≥ VMCV VCC applied or VCELL drops from ≥ VMCV to < VMCV DCMD high-to-low transition or to VSS on charge initiation and VEDV < VCELL < VMCV Charge initiation occurred and VTEMP ≥ VLTF or VTEMP ≤ VTCO or VCELL < VEDV Fast charging Charge pending complete and FAST = VCC Standard charging Charge pending complete and FAST = VSS Charge complete Top-off pending Top-off charging Trickle charging Fault Definitions: -∆V termination or VTEMP < VTCO or PVD ≥ 0 to -3mV/cell or maximum time-out or VCELL > VMCV VSEL = VCC, charge complete and VTEMP ≥ VLTF or VTEMP ≤ VTCO or VCELL < VEDV VSEL = VCC and charge complete and time-out not exceeded and VTEMP > VTCO and VCELL < VMCV Charge complete and top-off disabled or top-off complete or pending Charge pending state and charge pending time-out (tPEND) complete MOD Output Trickle charge per Table 4 DIS Output Low - Low Low High Trickle charge per Table 4 Low Low if VSNS > 250mV; high if VSNS < 200mV Low if VSNS > 250mV; high if VSNS < 200mV Low Low - - Trickle charge per Table 4 Low Activated per VSNS for 73ms of every 585ms Low Trickle charge per Table 4 Low Trickle charge per Table 4 Low VCELL = VBAT - VSNS; VMCV = 0.8 * VCC; VEDV = 0.262 * VCC or 0.4 * VCC; VTEMP = VTS - VSNS; VLTF = 0.5 * VCC. 5 bq2007 The charge status display is blanked during the charge pending state and when the battery pack is removed. is used for all the odd percentage charge indications to assure a monotonic charge status display. Charge Status Display Modes When MULT is pulled up to VCC, the bq2007 charge status monitor directly displays 1 32 of the charge safety timer as a percentage of full charge. This method is recommended over the voltage-based method when charging fixed-cell packs where the battery terminal voltages can vary greatly between packs. This method offers an accurate charge status indication when the battery is fully discharged. When using the timer-based method, discharge-before-charge is recommended. The bq2007 charge status monitor can be displayed in two modes summarized in Table 3. The display modes are a seven-segment monotonic bargraph or a sevensegment BCD single-digit format. When QDSEL is pulled down to VSS, pins SEGA–G drive the decoded seven segments of a single BCD digit display, and when QDSEL is pulled up to VCC, pins SEGA–G drive the seven segments of a bargraph display. During discharge with MULT pulled down to VSS, the charge status monitor indicates the percentage of the battery voltage by comparing VBAT to the internal discharge voltage reference thresholds. In BCD format, the discharge thresholds V80, V60, V40, and V20 correspond to a battery charge state indication of 90%, 70%, 50%, and 30%, respectively. In bargraph format, the same discharge thresholds correspond to a battery charge state indication of 90%, 60%, 40%, and 30%, respectively. Differences in the battery charge state indications are due to the finer granularity of the BCD versus the bargraph format. In the bargraph display mode, outputs SEGA–G allow options for a three-segment to seven-segment bargraph display. The three-segment charge status display uses outputs SEGB, SEGD, and SEGF for 30%, 60%, and 90% charge indications, respectively. The four-segment charge status display uses outputs SEGA, SEGC, SEGD, and SEG E for 20%, 40%, 60%, and 80% indications, respectively. The seven-segment charge status monitor uses all segments. The BCD display mode drives pins SEGA–G with the decoded seven-segment single-digit information. The display indicates in 10% increments from a BCD zero count at charge initiation to a BCD nine count indicating 90% charge capacity. Charge completion is indicated by the letter “F,” a fault condition by the letter “E,” and the discharge condition by the letter “d.” See Table 3. During discharge and when MULT is pulled up to VCC, the state-of-charge monitor BCD format displays the discharge condition, letter “d,” whereas the bargraph format has no indication. Table 2. bq2007 Charge Status Display Summary Mode DSEL1 = L DSEL2 = L (Mode 1) DSEL1 = H DSEL2 = L (Mode 2) DSEL1 = L DSEL2 = H (Mode 3) Note: Charge Action State Battery absent Charge pending (temp. limit, low voltage) Discharge in progress Charging Charge complete Fault (low-voltage time-out) Battery absent Discharge in progress, pending Charging Charge complete Fault (low-voltage time-out) Battery absent Charge pending (temp. limit, low voltage) Discharge in progress Charging Charge complete Fault (low-voltage time-out) LED1 0 0 0 Flashing 1 0 0 1 1 0 0 0 0 0 Flashing 1 0 1 = on; 0 = off; L = pulled down to VSS; H = pulled up to VCC. 6 LED2 0 Flashing 1 0 0 0 0 1 0 1 0 0 Flashing Flashing 0 0 1 DIS 0 0 1 0 0 0 0 1 0 0 0 0 0 1 0 0 0 ALARM 0 0 0 0 High tone High tone 0 0 0 High tone High tone 0 0 0 0 High tone High tone bq2007 Display Driver Modes Battery Voltage and Temperature Measurement The bq2007 is designed to interface with LCD or LED type displays. The LED signal levels are driven when the MSEL soft-programmed input is pulled to VCC at initialization. The output pin COM is the common anode connection for LED SEGA–G. The battery voltage and temperature are monitored within set minimum and maximum limits. When MULT is pulled up to VCC, battery voltage is sensed at the BAT pin by a resistive voltage divider that divides the terminal voltage between 0.262 ∗ VCC (VEDV) and 0.8 ∗ VCC (VMCV). The bq2007 charges multi-cell battery packs from a minimum of N cells, to a maximum of 1.5 ∗ N cells. The battery voltage divider is set to the minimum cell battery pack (N) by the BAT pin voltage divider ratio equation: The LCD interface mode is enabled when the MSEL soft-programmed input pin is pulled to VSS at initialization. An internal oscillator generates all the timing signals required for the LCD interface. The output pin COM is the common connection for static direct-driving of the LCD display backplane and is driven with an AC signal at the frame period. When enabled, each of the SEGA–G pins is driven with the correct-phase AC signal to activate the LCD segment. In bargraph or BCD mode, output pins SEGA–G interface to LED or LCD segments. R1 N = ( )−1 R2 1.33 When MULT is pulled down to V SS , tighter charge voltage limits and voltage-based charge status display are selected. This is recommended for charging packs with a fixed number of cells where the battery voltage divider range is between 0.4 ∗ VCC (VEDV) and 0.8 ∗ VCC Table 3. bq2007 Charge Status Display Summary Mode QDSEL = H QDSEL = L Note: Display Indication SEGA SEGB SEGC SEGD SEGE SEGF SEGG 20% charge 1 0 0 0 0 0 0 30% charge 1 1 0 0 0 0 0 40% charge 1 1 1 0 0 0 0 60% charge 1 1 1 1 0 0 0 80% charge 1 1 1 1 1 0 0 90% charge 1 1 1 1 1 1 0 Charge complete 1 1 1 1 1 1 1 0% charge—digit 0 1 1 1 1 1 1 0 10% charge—digit 1 0 1 1 0 0 0 0 20% charge—digit 2 1 1 0 1 1 0 1 30% charge—digit 3 1 1 1 1 0 0 1 40% charge—digit 4 0 1 1 0 0 1 1 50% charge—digit 5 1 0 1 1 0 1 1 60% charge—digit 6 1 0 1 1 1 1 1 70% charge—digit 7 1 1 1 0 0 1 0 80% charge—digit 8 1 1 1 1 1 1 1 90% charge—digit 9 1 1 1 1 0 1 1 Charge complete—letter F 1 0 0 0 1 1 1 Fault condition—letter E 1 0 0 1 1 1 1 Discharge—letter d 0 1 1 1 1 0 1 1 = on; 0 = off; L = pulled down to VSS; H = pulled up to VCC. 7 bq2007 R1 VCC VCC BAT TS bq2007 N T C bq2007 R2 SNS SNS RSNS RSNS VSS VSS BAT Voltage Connection Thermistor Connection NTC = negative temperature coefficient thermistor. FG200701.eps Figure 2. Voltage and Temperature Limit Measurement (VCELL) is compared to the low-voltage threshold (VEDV) and charge will be inhibited if VCELL < VEDV. The condition trickle current and fault time-out are a percentage of the fast charge rate and maximum time-out (MTO). (VMCV). The bq2007 charges fixed-cell battery packs of N cells. The battery voltage divider is set by the divider ratio equation: R1 N = ( )−1 R2 2 Initiating Charge Action and Discharge-Before-Charge Note: The resistor-divider network impedance should be above 200KΩ to protect the bq2007. A charge action is initiated under control of: (1) battery insertion or (2) power applied. Battery insertion is detected when the voltage at the BAT pin falls from above VMCV to below VMCV. Power applied is detected by the rising edge of VCC when a battery is inserted. When battery temperature is monitored for maximum and minimum allowable limits, the bq2007 requires that the thermistor used for temperature measurement have a negative temperature coefficient. See Figure 2. Discharge-before-charge (see Figure 3) is initiated automatically on application of power or battery insertion when DCMD is connected to VSS. Discharge-on-demand is initiated by a negative-going pulse on the DCMD pin Temperature and Voltage Prequalifications For charging to be initiated, the battery temperature must fall within predetermined acceptable limits. The voltage on the TS pin (VTS) is compared to an internal lowtemperature fault threshold (VLTF) of (0.5 ∗ VCC) and the high temperature cutoff voltage (VTCO) on the TCO pin. For charging to be initiated, VTS must be less than VLTF and greater than VTCO. Since VTS decreases as temperature increases, the TCO threshold should be selected to be lower than 0.5 ∗ VCC for proper operation. If the battery temperature is outside these limits, the bq2007 holds the charge-pending state with a pulse trickle current until the temperature is within limits. Temperature prequalification and termination is disabled if VTS is greater than 0.8 ∗ VCC. See Figure 2. DCMD bq2007 Always Discharge The bq2007 provides undervoltage battery protection by trickle-current conditioning of a battery that is below the low-voltage threshold (VEDV). The battery voltage DCMD bq2007 Discharge on Command Figure 3. Discharge-Before-Charge 8 bq2007 Table 4. bq2007 Charge Action Control Summary Trickle Rep Rate -∆V C 32 Trickle Rep Rate PVD C 64 2400 219Hz 109Hz 1200 109Hz 55Hz 600 55Hz 27Hz 100% 600 219Hz 109Hz 80 (C) 100% 300 109Hz 55Hz 40 (2C) 100% 150 55Hz 27Hz TM Input State Time-out Period (min) VSS Float 640 (C 8) 25% VSS VSS 320 (C 4 ) 25% VSS VCC 160 (C 2) 25% VCC Float 160 (C 2) VCC VSS VCC VCC regardless of charging activity. The DCMD pin is internally pulled up to VCC; therefore, not connecting this pin results in disabling the discharge-before-charge function. When the discharge begins, the DIS output goes high to activate an external transistor that connects a load to the battery. The bq2007 terminates dischargebefore-charge by detecting when the battery cell voltage is less than or equal to the end-of-discharge voltage (VEDV). Voltage Termination Hold-off To prevent early termination due to an initial false peak battery voltage, the -∆V and PVD terminations are disabled during a short “hold-off” period at the start of charge. During the hold-off period when fast charge is selected (FAST = 1), the bq2007 will top off charge to prevent excessive overcharging of a fully charged battery. Once past the initial charge hold-off time, the termination is enabled. TCO and MCV terminations are not affected by the hold-off time. Charge State Actions Once the required discharge is completed and temperature and voltage prequalifications are met, the charge state is initiated. The charge state is configured by the VSEL, FAST, and TM input pins. The FAST input selects between Fast and Standard charge rates. The Standard charge rate is 1 4 of the Fast charge rate, which is accomplished by disabling the regulator for a period of 286µs of every 1144µs (25% duty cycle). In addition to throttling back the charge current, time-out and hold-off safety time are increased accordingly. See Table 4. -∆V or PVD Termination Table 5 summarizes the two modes for full-charge voltage termination detection. When V SEL = V SS , negative delta voltage detection occurs when the voltage seen on the BAT pin falls 12mV (typical) below the maximum sampled value. V SEL = V CC selects peak voltage detect termination and the top-off charge state. PVD termination occurs when the BAT pin voltage falls 6mV per cell below the maximum sampled value. When charging a battery pack with a fixed number of cells, the -∆V and PVD termination thresholds are -6mV and 0 to -3mV per cell, respectively. The valid battery voltage range on VBAT for -∆V or PVD termination is from 0.262 ∗ VCC to 0.8 ∗ VCC. The VSEL input selects the voltage termination method. The termination mode sets the top-off state and trickle charge current rates. The TM input selects the Fast charge rate, the Standard rate, and the corresponding charge times. Once charging begins at the Fast or Standard rate, it continues until terminated by any of the following conditions: n Negative delta voltage (-∆V) n Peak voltage detect (PVD) n Hold-off period (sec) MOD Duty Cycle FAST Input State Table 5. VSEL Configuration VSEL Detection Method Top-Off Maximum temperature cutoff (TCO) VSS -∆V Disabled C n Maximum time-out (MTO) VCC PVD Enabled C n Maximum cutoff voltage (MCV) 9 Pulse Trickle Rate 32 64 bq2007 Maximum Temperature, Maximum Voltage, and Maximum Time Safety Terminations DC Source Switch bq2007 The bq2007 also terminates charge action for maximum temperature cutoff (TCO), maximum cutoff voltage (MCV), and maximum time-out (MTO). Temperature is monitored as a voltage on the TS pin (VTS), which is compared to an internal high-temperature cutoff threshold of VTCO. The TCO reference level provides the maximum limit for battery temperature during charging. MCV termination occurs when VCELL > VMCV. The maximum time-out (MTO) termination is when the charger safety timer countdown has completed during the active charge state. If the MTO, MCV, or TCO limit is exceeded during Fast charge, Standard charge, or top-off states, charge action is terminated. MOD Battery Under Charge SNS RSNS Figure 4. Constant-Current Switching Regulation Top-Off and Pulse Trickle Charging Charge Inhibit The bq2007 provides a post-detection timed charge capability called top-off to accommodate battery chemistries that may have a tendency to terminate charge prior to achieving full capacity. When VSEL = VCC, the top-off state is selected; charging continues after Fast charge termination for a period equal to the time-out value. In top-off mode, the Fast charge control cycle is modified so that MOD is activated for a pulse output of 73ms of every 585ms. This results in a rate 1 8 that of the Fast charge rate. Top-off charge is terminated by maximum temperature cutoff (TCO), maximum cutoff voltage (MCV), or maximum time-out termination. Fast charge, top-off, and pulse trickle may be inhibited by using the INH input pin. When low, the bq2007 suspends all charge activity, drives all outputs to high impedance, and assumes a low-power operational state. When INH returns high, a fast-charge cycle is qualified and begins as soon as conditions allow. Charge Current Control The bq2007 controls charge current through the MOD output pin. In a frequency-modulated buck regulator configuration, the control loop senses the voltage at the SNS pin and regulates to maintain it between 0.04 ∗ VCC and 0.05 ∗ VCC. The nominal regulated current is IREG = 0.225V/RSNS. See Figure 4. Pulse trickle is used to compensate for self-discharge while the battery is idle and to condition a depleted low-voltage battery to a valid voltage prior to highcurrent charging. The battery is pulse trickle charged when Fast, Standard, or top-off charge is not active. The MOD output is active for a period of 286µs of a period specified in Table 4. This results in a trickle rate of C 64 for PVD and C 32 when -∆V is enabled. MOD pin is switched high or low depending on the voltage input to the SNS pin. If the voltage at the SNS pin is less than VSNSLO (0.04 ∗ VCC nominal), the MOD output is switched high to gate charge current through the inductor to the battery. When the SNS voltage is greater than VSNSHI (0.05 ∗ VCC nominal), the MOD output is switched low-shutting off charge current from the supply. The MOD pin can be used to gate an external charging current source. When an external current source is used, no sense resistor is required, and the SNS pin is connected to VSS. 10 bq2007 Absolute Maximum Ratings Minimum Maximum Unit VCC Symbol VCC relative to VSS -0.3 +7.0 V VT DC voltage applied on any pin excluding VCC relative to VSS -0.3 +7.0 V TOPR Operating ambient temperature -20 +70 °C TSTG Storage temperature -40 +85 °C TSOLDER Soldering temperature - +260 °C Note: Parameter VSNSHI VSNSLO VLTF VHTF VEDV VMCV V20 V40 V60 V80 V20 V40 V60 V80 Commercial Permanent device damage may occur if Absolute Maximum Ratings are exceeded. Functional operation should be limited to the Recommended DC Operating Conditions detailed in this data sheet. Exposure to conditions beyond the operational limits for extended periods of time may affect device reliability. DC Thresholds Symbol Notes (TA = TOPR; VCC = 5V ± 10%) Parameter High threshold at SNS resulting in MOD = Low Low threshold at SNS resulting in MOD = High TS pin low-temperature threshold TS pin high-temperature threshold End-of-discharge voltage MULT is pulled up to VCC End-of-discharge voltage MULT is pulled down to VSS BAT pin maximum cell voltage threshold 20% state-of-charge voltage threshold at the BAT pin 40% state-of-charge voltage threshold at the BAT pin 60% state-of-charge voltage threshold at the BAT pin 80% state-of-charge voltage threshold at the BAT pin 20% state-of-charge voltage threshold at the BAT pin 40% state-of-charge voltage threshold at the BAT pin 60% state-of-charge voltage threshold at the BAT pin 80% state-of-charge voltage threshold at the BAT pin Rating Tolerance Unit 0.05 * VCC ± 25 mV 0.04 * VCC ± 10 mV 0.5 * VCC ± 30 mV SNS = 0V VTCO ± 30 mV SNS = 0V 0.262 * VCC ± 30 mV SNS = 0V 0.4 * VCC ± 30 mV SNS = 0V 0.8 * VCC ± 30 mV SNS = 0V 320 * VCC ± 30 mV 320 * VCC ± 30 mV 320 * VCC ± 30 mV 320 * VCC ± 30 mV 320 * VCC ± 30 mV 320 * VCC ± 30 mV 320 * VCC ± 30 mV 320 * VCC ± 30 mV 187 191 195 203 158 163 167 171 11 Notes Fast or standard charge state; MULT pulled to VSS Fast or standard charge state; MULT pulled to VSS Fast or standard charge state; MULT pulled to VSS Fast or standard charge state; MULT pulled to VSS Discharge-before-charge state; MULT pulled to VSS; DIS = 1 Discharge-before-charge state; MULT pulled to VSS; DIS = 1 Discharge-before-charge state; MULT pulled to VSS; DIS = 1 Discharge-before-charge state; MULT pulled to VSS; DIS = 1 bq2007 Recommended DC Operating Conditions (TA = 0 to +70°C) Symbol Parameter inimum Typical Maximum Unit 4.5 5.0 5.5 V Notes VCC Supply voltage VBAT Voltage on BAT pin 0 - VCC V VTS Voltage on TS pin 0 - VCC V Thermistor input VTCO Temperature cutoff on TCO 0 - 0.5 * VCC V Note 2 VCELL Battery voltage potential 0 - VCC V VBAT - VSNS VTEMP Voltage potential on TS 10% 0 - VCC V VTS - VSNS 2.0 - - V DCMD, FAST, VSEL, INH VCC - 0.3 - - V TM Logic input low - - 0.8 V DCMD, FAST, VSEL, INH Tri-level input low - - 0.3 V TM VOH Logic output high VCC - 0.8 - - V DIS, LED1–2, SEGA–G @ IOH = -10mA; MOD @ IOH = -5mA VOL Logic output low - - 0.8 V DIS, LED1–2, SEGA–G @ IOL = 10mA; MOD @ IOL = 5mA VIH Logic input high Tri-level input high VIL VOHCOM COM output VCC - 0.8 - - V IOHCOM COM source -40 - - mA @ VOHCOM = VCC - 0.8V ICC Supply current - 1 2.5 mA No output load IOH DIS, LED1–2, SEGA–G source -10 - - mA @VOH = VCC - 0.8V IOH MOD -5 - - mA @VOH = VCC - 0.8V IOL DIS, LED1–2, SEGA–G sink 10 - - mA @VOL = VSS + 0.8V IOL MOD 5 - - mA @VOL = VSS + 0.8V IIZ Tri-state inputs floating for Z state -2.0 - 2.0 µA TM Input leakage - - ±1 µA INH, VSEL, V = VSS to VCC Input leakage 50 - 400 µA DCMD, FAST, V = VSS to VCC IL @ IOHCOM = -40mA IIL Logic input low current - - 70 µA TM, V = VSS to VSS + 0.3V IIH Logic input high current -70 - - µA TM, V = VCC - 0.3V to VCC 12 bq2007 Impedance Symbol Minimum Typical Maximum Unit RI DC input impedance: pins TS, BAT, SNS, TCO 50 - - MΩ RPROG Soft-programmed pull-up resistor 150 - 200 KΩ MSEL, DSEL1, DSEL2, MULT, QDSEL; resistor value ± 10% tolerance RFLT Float state external resistor - 5 - MΩ TM Minimum Typical Maximum Unit Timing Symbol Parameter Notes (TA = 0 to +70°C; VCC ± 10%) Parameter Notes At VCC = ± 10%, TA = 0 to 60°C; see Table 3 dFCV Deviation of fast charge safety time-out 0.84 1.0 1.16 - tREG MOD output regulation frequency - - 300 kHz tPEND Charge pending time-out - 25 - % Ratio of fast charge time-out; see Table 4. FCOM Common LCD backplane frequency - 73 - Hz LCD segment frame rate FALARM Alarm frequency output - 3500 - kHz High tone tPW Pulse width for DCMD and INH pulse command 1 - - µs Signal valid time tMCV Valid period for VCELL > VMCV 0.5 - 1 sec If VCELL ≥ VMCV for tMCV during charge or top-off, then a transition is recognized as a battery replacement. Note: Typical is at TA = 25°C, VCC = 5.0V. 13 Typical regulation range; VCC = 5.0V bq2007 24-Pin DIP Narrow (PN) 24-Pin PN (0.300" DIP) Inches Millimeters Dimension Min. Max. Min. Max. A 0.160 0.180 4.06 4.57 A1 0.015 0.040 0.38 1.02 B 0.015 0.022 0.38 0.56 B1 0.045 0.055 1.14 1.40 C 0.008 0.013 0.20 0.33 D 1.240 1.280 31.50 32.51 E 0.300 0.325 7.62 8.26 E1 0.250 0.300 6.35 7.62 e 0.300 0.370 7.62 9.40 G 0.090 0.110 2.29 2.79 L 0.115 0.150 2.92 3.81 S 0.070 0.090 1.78 2.29 S: 24-Pin S (0.300" SOIC) 24-Pin S (0.300" SOIC) Inches B e D E Millimeters Dimension A Min. Max. Min. Max. 0.095 0.105 2.41 2.67 A1 0.004 0.012 0.10 0.30 B 0.013 0.020 0.33 0.51 C 0.008 0.013 0.20 0.33 D 0.600 0.615 15.24 15.62 E 0.290 0.305 7.37 7.75 e 0.045 0.055 1.14 1.40 H 0.395 0.415 10.03 10.54 L 0.020 0.040 0.51 1.02 H A C .004 A1 L 14 bq2007 Data Sheet Revision History Change No. Page No. 1 11 Note: Description Nature of Change Was VSNSHI - (0.01 * VCC); is 0.04 * VCC VSNSLO Rating Change 1 = Sept. 1996 B changes from Dec. 1995. Ordering Information bq2007 Temperature: blank = Commercial (-20 to +70°C) N = Industrial (-40 to +85°C)* Package Option: PN = 24-pin narrow plastic DIP S = 24-pin SOIC Device: bq2007 Fast-Charge IC * Contact factory for availability. 15 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. 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