L6924U STMicroelectronics, L6924U Datasheet
L6924U
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L6924U Summary of contents
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... Cellular phones ■ Digital still cameras ■ Standalone chargers ■ Wireless appliances Table 1. Device summary Order codes L6924U013 L6924U013TR September 2010 USB compatible battery charger system Package VFQFPN16 Doc ID 14716 Rev 2 L6924U VFQFPN16 Packaging Tube Tape and reel 1/37 www.st.com 37 ...
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... Maximum charging time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 8 Application information: monitoring and protection . . . . . . . . . . . . . . 22 8.1 NTC thermistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 8.2 Battery absence detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 8.3 Status pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 8.4 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 9 Additional applications information . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 9.1 Selecting the input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 9.2 Selecting the output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2/37 Doc ID 14716 Rev 2 L6924U ...
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... L6924U 9.3 Layout guidelines and demonstration board . . . . . . . . . . . . . . . . . . . . . . . 28 10 Application idea: dual input management with AC priority . . . . . . . . 31 11 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 12 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Doc ID 14716 Rev 2 Contents 3/37 ...
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... MOSFET, reverse blocking diode, sense resistor and thermal protection into a compact VFQFPN16 package. When an external voltage regulated adapter or USB port is used, the L6924U works in linear mode, and charges the battery in a constant current constant voltage (CC/CV) profile. Moreover, when a current-limited adapter is used, the device can operate in quasi-pulse mode, dramatically reducing the power dissipation ...
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... L6924U 2 Pin description Figure 3. Pin connection (top view) 2.1 Pin description Table 2. Pin functions Pin I Name V Input pin of the power stage. IN Supply voltage pin of the signal circuitry. V The operating input voltage ranges from 2 and the INSNS start-up threshold -ST Open-collector status pins. ...
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... The voltage across the resistor is proportional to the current delivered to the battery (gas gauge function). Selects pin AC adapter or USB port input modes. A high level sets the L6924U in USB mode while a low level sets the L6924U in the MODE AC adapter mode. When the AC adapter input is selected, the ISEL pin status does not affect the current set ...
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... L6924U 3 Maximum ratings Stressing the device above the rating listed in the “absolute maximum ratings” table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the operating sections of this specification is not implied ...
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... MODE at HIGH, ISEL at HIGH kΩ USB MODE at HIGH, ISEL at LOW kΩ USB R = 3.3 kΩ END TPRG R kΩ PRG C = 5.6n F TPRG kΩ PRG Status on Doc ID 14716 Rev 2 L6924U Min. Typ. Max. Unit 2 4.1 V 1.8 2 µA 500 nA 500 nA 4.16 4.2 4.24 V 450 ...
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... L6924U Table 5. Electrical characteristics (continued) Symbol Parameter Power MOSFET resistance R (3) DS(on) NTC pin hot threshold voltage TH NTC pin cold threshold voltage 1. T from -40 °C to 125 ° Guaranteed by design 3. Device working in quasi pulse mode Test condition Charge current = 500 mA Doc ID 14716 Rev 2 Electrical characteristics Min ...
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... BODY VDD CONTROL Mos Logic Driver Logic VDD VBG Charge BG Control THERMAL CONTROL LOGIC ST2 GND ST1 Doc ID 14716 Rev 2 Logic Logic I FAULT I DETECT Gas Gauge 4.2V CA-VA-TA REG VREF VPRE VDD NTC/PTC MANAG. OSC VDD L6924U VOUT IEND VOSNS VREF TH ...
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... It normally works as a linear charger when powered from an external voltage regulated adapter or USB port. However, thanks to its very low minimum input voltage (down to 2.5 V) the L6924U can also work as a quasi-pulse charger when powered from a current limited adapter. To work in this condition enough to set the device’s charging current higher than the adapter’s one (Chapter 6 ...
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... AC-DC adapter that is, in turn, the input voltage ADP of the L6924U. If the battery voltage is lower than the default pre-charge voltage (V the pre-charge phase takes place. The battery is pre-charged with a low current, internally set the fast charge current. ...
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... L6924U Figure 6. Typical charge curves in linear mode Pre-Charge Phase V ADP V OPRGTH V PRETH I CHG I PRETH The worst case in power dissipation occurs when the device starts the fast-charge phase. In fact, the battery voltage is at its minimum value. In this case, there is the maximum difference between the adapter voltage and battery voltage, and the charge current is at its maximum value ...
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... In this case, the fast charge current must be set higher than the current limit of the adapter. In this mode, the L6924U charges the battery with the same three phases as in Linear Mode, but the power dissipation is greatly reduced ...
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... L6924U Where ΔV is given by: MOS Equation 3 Where current limit of the wall adapter, and R LIM The difference between the programmed charge current and the adapter limit should be high enough to minimize the R control loop completely unbalanced and the power element is fully turned on. ...
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... The drawback is the high power dissipation. The advantage of the quasi-pulse charging method is that the power dissipated is dramatically reduced. The drawback is that a dedicated upstream adapter is required. 16/37 = − × DIS ADP BAT LIM Doc ID 14716 Rev 2 L6924U ...
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... L6924U 7 Applications information: charging process Figure 9. Charging process flow chart 7.1 Pre-charge phase The L6924U allows pre-charging the battery with a low current when the battery is deeply discharged. Applications information: charging process Doc ID 14716 Rev 2 17/37 ...
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... A low level sets the L6924U in AC mode. The fast charge current is determined by the resistor connected to the I connected to I USB On the other hand, a high level at the MODE pin sets the L6924U in USB mode. The fast charge current is determined by the resistor connected to the I charge phase ), regardless of the resistor connected to I Figure 10 ...
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... L6924U Equation 6 Where V is the internal reference equal to 1.23 V, whereas K BG 9500. Figure 11. I pin connection AC In USB mode (MODE pin high), the R Equation 7 Where V and K BG The charge current in USB mode depends on R When this pin is high, the “high-power” USB mode is selected and the charge current is determined by the equation 7 ...
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... ENDTH = T DEGLITCH Chapter 7.7 on page 21 Doc ID 14716 Rev 2 . This current can be selected by an Figure 13 , whose value can be ⎛ ⎞ K END ⎜ ⎜ ⎟ ⎟ ⎝ ⎠ ENDTH T MAXCH 220 ) can be used by a END L6924U is END ...
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... V. 7.7 Maximum charging time To avoid the charging of a dead battery for a long time, the L6924U has the possibility to set a maximum charging time starting from the beginning of the fast-charge phase. This timer can be set through a capacitor, connected between the T external capacitor (in nF) and is given by the following equation: ...
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... When the device is charged in low power USB mode, in order to take into account the reduced charge current, the maximum charging time is proportionally increased (five times the maximum charging time calculated with R 22/37 pin connection or R USB MAXPRECH 8 USB Doc ID 14716 Rev × T MAXCH , a fault signal is PRETH ). L6924U ...
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... L6924U 8 Application information: monitoring and protection The L6924U uses a VFQFPN ( mm) 16-pin package with an exposed pad that allows the user to have a compact application and good thermal behavior at the same time. The L6924U has a low thermal resistance because of the exposed pad (approximately 75 °C/W, depending on the board characteristics). Moreover, a built-in thermal protection feature prevents the L6924U from having thermal issues typically present in a linear charger ...
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... BAT Figure 18. Voltage window with hysteresis MINTH_HYS V MAXTH_HYS Figure 19. Pin connection When the TH pin voltage rises and exceeds the V L6924U stops the charge, and indicates a fault by the status pins. The device re-starts to 24/37 Figure 900mV MINTH 780mV Voltage Variation on TH pin ...
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... Equation 15 Where R NTC50°C that: Equation 16 Consequently: Equation 17 Application information: monitoring and protection (225 mV Typ.), the L6924U stops the charge until the TH pin REF = 248 mV (typ.). MAXTH_HYS = × MINTH REF R is equal to 1 ...
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... T ° HYS 0 C × 900 051 − 225 mV 248 ° HYS 50 C × 225 039 Doc ID 14716 Rev 2 HYS T is the pin voltage TH_HYS values, see T mV ° ° ≅ ≅ − L6924U . ...
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... L6924U 8.2 Battery absence detection This feature provides a battery absent detection scheme to detect the removal or the insertion of the battery. If the battery is removed, the charge current falls below the I At the end of the de-glitch time, a detection current I output for a time current equal to I ...
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... Over time 8.4 Shutdown The L6924U has a shutdown pin; when the pin is connected to GND, the device is operating. When the pin is left floating, the device enters the shutdown mode, the consumption from the input is dramatically reduced to 60 µA (typ.). In this condition, V 28/37 ...
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... L6924U 9 Additional applications information 9.1 Selecting the input capacitor In most applications µF ceramic capacitor, placed close to the V be used to filter the high frequency noise. 9.2 Selecting the output capacitor Typically, a 4.7 µF ceramic capacitor placed close to the V keep voltage control loop stable . This ensures proper operation of battery absent detection in removable battery pack applications ...
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... OSNS as possible to the battery. The demonstration board layout and schematic are shown in Figure 23 , Figure 24 Figure 23. Demonstration board layout, top side Figure 24. Demonstration board layout, bottom side 30/37 and Figure 25 . Doc ID 14716 Rev 2 L6924U ...
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... L6924U Figure 25. Demonstration board schematic Table 7. Demonstration board components description Name Value R1 24 kΩ AC mode fast-charge current resistor. Used to set the charging current in AC mode. USB mode fast-charge current resistor. Used to set the charging current in USB R2 24 kΩ mode. End of Charge current resistor. Used to set the termination current and “gas R3 3.3 kΩ ...
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... A correct choice of this diode is important to limit V possible to AC. In this condition the MODE pin is low. This sets the L6924U in AC mode and the battery is charged with the current programmed by R When only the USB power source is available, both Q1 and Q2 switch on and the pin V connected to USB ...
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... L6924U Figure 26. Dual input management AC AC USB USB Application idea: dual input management with AC priority Doc ID 14716 Rev OUT OUT Li-Ion Li-Ion battery battery L6924U L6924U I I USB USB USB USB MODE MODE 33/37 ...
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... Package mechanical data 11 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ® ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: ® ECOPACK trademark. 34/37 Doc ID 14716 Rev 2 L6924U ® www.st.com . ...
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... L6924U Table 8. VFQFPN16 ( mm.) mechanical data Dim Figure 27. Package dimensions mm. Min. Typ. 0.80 0.90 0.02 0.65 0.20 0.18 0.25 2.85 3.00 1.45 1.60 2.85 3.00 1.45 1.60 0.45 0.50 0.30 0.40 Doc ID 14716 Rev 2 Package mechanical data Max. 1.00 0.05 1.00 0.30 3 ...
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... Revision history 12 Revision history Table 9. Document revision history Date 20-May-2008 22-Sep-2010 36/37 Revision 1 First release 2 Modified: Table 8 and Doc ID 14716 Rev 2 Changes Figure 27 on page 35. Minor changes. L6924U ...
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... L6924U Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...