MP2633GR-P

MP2633 1.5A Single Cell Switch Mode Battery Charger with Power Path Management and Boost OTG The Future of Analog IC Technology DESCRIPTION FEATURES The MP2633 is a highly-integrated, flexible, switch-mode battery charge management and system power path management device for a single-cell Li-ion and Li-Polymer battery used in a wide range of portable applications.   The MP2633 has two operating modes—charge mode and boost mode—to allow management of system and battery power based on the state of the input. When input power is present, the device operates in charge mode. It automatically detects the battery voltage and charges the battery in the three phases: trickle current, constant current and constant voltage. Other features include charge termination and autorecharge. This device also integrates both input-current limit and input-voltage regulation in order to manage input power and meet the priority of the system power demand. . In the absence of an input source, the MP2633 switches to boost mode through the MODE pin to power the SYS pins from the battery. The OLIM pin programs the output current limit in boost mode. The MP2633 also allows an output short-circuit thanks to an output disconnect feature, and can auto-recover when the short circuit fault is removed. The MP2633 provides full operating status indication to distinguish charge mode from boost mode.            4.5V-to-6V Operating Input Voltage Range Power Management Function Integrated Input-Current Limit and Input-Voltage Regulation Up to 1.5A Programmable Charge Current Trickle-Charge Function Selectable 3.6V/ 4.2V Charge Voltage with 0.5% Accuracy Negative Temperature Coefficient Pin for Battery Temperature Monitoring Programmable Timer Back-Up Protection Thermal Regulation and Thermal Shutdown Internal Battery Reverse Leakage Blocking Reverse Boost Operation Mode for System Power Up to 91% 5V Boost Mode Efficiency @ 1A Programmable Output Current Limit for Boost Mode Integrated Short Circuit Protection for Boost Mode APPLICATIONS   Sub-Battery Applications Power-Bank Applications for Smart-Phone Tablet and other Portable Device All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Products, Quality Assurance page. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. The MP2633 achieves low EMI/EMC performance with well-controlled switching edges. To guarantee safe operation, the MP2633 limits the die temperature to a preset value 120oC. Other safety features include input over-voltage protection, battery over-voltage protection, thermal shutdown, battery temperature monitoring, and a programmable timer to prevent prolonged charging of a dead battery. MP2633 Rev. 1.08 4/27/2016 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 1 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER TYPICAL APPLICATION Table 1: Operation Mode Power Source __________ ACOK EN High MODE Charge Mode, Enable Charging 0.8VVBATT+300mV Figure 9: Battery Power Start-Up Time Flow in Boost Mode MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 21 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER START UP TIME FLOW IN BOOST MODE Condition: VIN = 0V, /Boost is always pulled up to an external constant 5V. VBATT 2.9V VCC follows VSYS VCC follows VBATT VCC 2.2V 5V 0V MODE 5V Band Gap 0V 5V BOOST 0V 1.2ms Boost SS VSYS Down  Mode 0V VSYS >V BATT+300mV Figure 10: Mode Start-Up Time Flow in Boost Mode MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 22 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER OPERATION INTRODUCTION The MP2633 is a highly-integrated, synchronous, switching charger with bi-directional operation for a boost function that can step-up the battery voltage to power the system. Depending on the VIN value, it operates in one of three modes: charge mode, boost mode and sleep mode. In charge mode, the MP2633 supports a precision Li-ion or Li-polymer charging system for singlecell applications. In boost mode, MP2633 boosts the battery voltage to VSYS to power highervoltage systems. In sleep mode, the MP2633 stops charging or boosting and operates at a low current from the input or the battery to reduce power consumption when the IC isn’t operating. The MP2633 monitors VIN to allow smooth transition between different modes of operation. CHARGE MODE OPERATION Charge Cycle (Trickle ChargeCC ChargeCV Charge) CC>>>CV Threshold ICHG Constant Charge Current VBAT TC>>>CC Threshold Trickle Charge Current Trickle charge CC charge CV charge Charge Full a) Without input current limit Constant Charge Current CC>>>CV Threshold ICHG Input Current Limit VBAT TC>>>CC Threshold Trickle Charge Current Trickle charge CC charge CV charge Charge Full b) With input current limit In charge mode, the MP2633 has five control loops to regulate the input current, input voltage, charge current, charge voltage, and device junction temperature. It charges the battery in three phases: trickle current (TC), constant current (CC), and constant voltage (CV). While charging, all four loops are active but only one determines the IC behavior. Figure 11(a) shows a typical battery charge profile. The charger stays in TC charge mode until the battery voltage reaches a TC-to-CC threshold. Otherwise the charger enters CC charge mode. When the battery voltage rises to the CV-mode threshold, the charger operates in constant voltage mode. Figure 11 (b) shows a typical charge profile when the input-current-limit loop dominates during the CC charge mode, and in this case the charge current exceeds the input current, resulting in faster charging than a traditional linear solution that is well-suited for USB applications. Auto-Recharge Once the battery charge cycle completes, charger remains off. During this process, system load may consume battery power, or battery may self discharge. To ensure that battery will not go into depletion, a new charge cycle automatically begins when the battery the the the the Figure 11: Typical Battery Charginge Profile voltage falls below the auto-recharge threshold and the input power is present. The timer resets when the auto-recharge cycle begins. During the off state after the battery is fully charged, if the input power re-starts or the EN signal refreshes, the charge cycle will start and the timer will reset no matter what the battery voltage is. Battery Over-Voltage Protection The MP2633 has battery over-voltage protection. If the battery voltage exceeds the battery overvoltage threshold, (103.3% of the battery-full voltage), charging is disabled. Under this condition, an internal current source draws a current from the BATT pin to decrease the battery voltage and protect the battery. Timer Operation in Charge Mode The MP2633 uses an internal timer to terminate the charging. The timer remains active during the charging process. An external capacitor between TMR and GND programs the charge cycle duration. MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 23 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER If charging remains in TC mode beyond the trickle-charge time τTOTAL_TMR, charging will terminate. The following determines the length of the trickle-charge period: TRICKLE _ TMR  60mins  CTMR (F) 1A  (1) 0.1F ICHG (A) The maximum total charge time is: TOTAL _ TMR  6Hours  CTMR (F) 1A  (2) 0.1F ICHG (A) Negative Temperature Coefficient (NTC) Input for Battery Temperature Monitoring The MP2633 has a built-in NTC resistance window comparator, which allows the MP2633 to monitor the battery temperature via the batteryintegrated thermistor. Connect an appropriate resistor from VSYS to the NTC pin and connect the thermistor from the NTC pin to GND. The resistor divider determines the NTC voltage depending on the battery temperature. If the NTC voltage falls outside of the NTC window, the MP2633 stops charging. The charger will then restart if the temperature goes back into NTC window range. Input-Current Limiting in Charge Mode The MP2633 has a dedicated pin that programs the input-current limit. The current at ILIM is a fraction of the input current; the voltage at ILIM indicates the average input current of the switching regulator as determined by the resistor value between ILIM and GND. As the input current approaches the programmed input current limit, charge current is reduced to allow priority to system power. Use the following equation to determine the input current limit threshold, IILIM = 40.5(kΩ) (A) RILIM (kΩ) In charge mode, if the input power source is not sufficient to support both the charge current and system load current, the input voltage will decrease. As the input voltage approaches the programmed input voltage regulation value, charge current is reduced to allow priority of system power and maintain the input voltage avoid dropping further. The input voltage can be regulated by a resistor divider from VIN pin to REG pin to AGND according to the following expression: VIN _ R  VREG  R3  R5 R5 (4) Where: the VREG is the internal voltage reference, 1.2V. Setting the Charge Current The external sense resistors, RS1 and RISET, program the battery charge current, ICHG. Select RISET based on RS1: ICHG (A)= 70(kΩ) 40(mV)  RISET (kΩ) RS1(mΩ) (5) Where: the 40mV is the charge current limit reference. Battery Short Protection The MP2633 has two current limit thresholds. CC and CV modes have a peak current limit threshold of 3A, while TC mode has a current limit threshold of 1.5A. Therefore, the current limit threshold decreases to 1.5A when the battery voltage drops below the TC threshold. Moreover, the switching frequency also decreases when the BATT voltage drops to 40% of the charge-full voltage. Thermal Foldback Function (3) Input Over-Current Protection The MP2633 features input over-current protection (OCP): when the input current exceeds 3A, Q2 is controlled linearly to regulate the current. If the current still exceeds 3A after a 120µs blanking time, Q2 will turn off. A fast off function turns off Q2 quickly when the input current exceeds 7A to protect both Q1 and Q2. The MP2633 implements thermal protection to prevent thermal damage to the IC and the surrounding components. An internal thermal sense and feedback loop automatically decreases the programmed charge current when the die temperature reaches 120°C. This function is called the charge-current-thermal foldback. Not only does this function protect against thermal damage, it can also set the charge current based Input Voltage Regulation in Charge Mode MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 24 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER on requirements rather than worst-case conditions while ensuring safe operation. Furthermore, the part includes thermal shutdown protection where the ceases charging if the junction temperature rises to 150°C. Fully Operation Indication The MP2633 integrates indicators for following conditions as shown in Table 2. the Table 2: Indicator for Each Operation Mode ---------------- Operation ACOK Charging Charge Mode ------------ CHG ------------------- BOOST Low End of Charge, charging disabled Low High High Blinking NTC Fault, Timer Out Boost Mode High High Low Sleep Mode, VCC absent High High High BOOST MODE OPERATION Low-Voltage Start-Up The minimum battery voltage required to start up the circuit in boost mode is 2.9V. Initially, when VSYS < VBATT, the MP2633 works in down mode. In this mode, the synchronous P-MOSFET stops switching and its gate connects to VBATT statically. The P_MOSFET keeps off as long as the voltage across the parasitic CDS (VSW) is lower than VBATT. When the voltage across CDS exceeds VBATT, the synchronous P-MOSFET enters a linear mode allowing the inductor current to decrease and flowing into the SYS pin. Once VSYS exceeds VBATT, the P-MOSFET gate is released and normal closed-loop PWM operation is initiated. In boost mode, the battery voltage can drop to as low as 2.5V without affecting circuit operation. SYS Disconnect and Inrush Limiting The MP2633 allows for true output disconnect by eliminating body diode conduction of the internal P-MOSFET rectifier. VSYS can go to 0V during shutdown, drawing no current from the input source. It also allows for inrush current limiting at start-up, minimizing surge currents from the input supply. To optimize the benefits of output disconnect, avoid connecting an external Schottky diode between the SW and SYS pins. Board layout is extremely critical to minimize voltage overshoot at the SW pin due to stray inductance. Keep the output filter capacitor as close as possible to the SYS pin and use very low ESR/ESL ceramic capacitors tied to a good ground plane. Boost Output Voltage In the boost mode, the MP2633 programs the output voltage via the external resistor divider at FB pin, and provides built-in output over-voltage protection (OVP) to protect the device and other components against damage when VSYS goes beyond 6V. Should output over-voltage occur, the MP2633 turns off the boost converter. Once VSYS drops to a normal level, the boost converter restarts again as long as the MODE pin remains in active status. Boost Output-Current Limiting The MP2633 integrates a programmable output current limit function in boost mode. If the boost output current exceeds this programmable limit threshold, the output current will be limited at this level and the SYS voltage will start to drop down. The OLIM pin programs the current limit threshold up to 1.5A as per the following equation: 70(k) 40(mV) IOLIM( A)    1.7 (6) ROLIM(k) RS1((m) Where: the 40mV is the charge current limiting reference. SYS Output Over Current Protection The MP2633 integrates three-phase output overcurrent protection. Phase one (boost mode): when the output current exceeds the output current limit, the MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 25 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER output constant current loop controls the output current, the output current remains at its limit of IOLIM, and VSYS decreases. Phase two (down mode): when VSYS drops below VBATT+100mV and the output current loop remains in control, the boost converter enters down mode and shutdown after a 120μs blanking time. Phase three (short circuit mode): when VSYS drops below 2V, the boost converter shuts down immediately once the inductor current hits the fold-back peak current limit of the low side NMOSFET. The boost converter can also recover automatically after a 1ms deglitch period. Thermal Shutdown Protection Thermal shutdown protection is also active in boost mode. Once the junction temperature rises higher than 150°C, the MP2633 enters thermal shutdown. It will not resume normal operation until the junction temperature drops below 120°C. MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 26 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER APPLICATION INFORMATION COMPONENT SELECTION Setting the Charge Current in Charge Mode In charge mode, both the external sense resistor, RS1, and the resistor RISET connect to the ISET pin to set the charge current (ICHG) of the MP2633 (see the Typical Application circuit). Given ICHG and RS1, the regulation threshold, VIREF, across this resistor is: VIREF (mV )  RS1(m  )  ICHG ( A ) RISET sets VIREF as per the following equation: VIREF (mV )  70(k )  40(mV ) R ISET (k ) (7) If the voltage on PWIN is between 0.8V and 1.15V, the MP2633 works in the charge mode. While the voltage on the PWIN pin is not in the range of 0.8V to 1.15V and VIN > 2V, the MP2633 works in the boost mode (see MPS. All Rights Reserved.). For a wide operating range, use a maximum input voltage of 6V as the upper threshold for a voltage ratio of: VPWIN 1.15 R6   VIN 6 R4  R6 With the given R6, R4 is then: (8 ) R4  So, the RISET can be calculated as: 70(k ) RISET (k )   40(mV ) VIREF (mV ) (9 ) For example, for ICHG=1.5A and RS1=50mΩ: VIREF=75mV, so RISET=37.4kΩ. Setting the Input Current Limiting in Charge Mode In charge mode, connect a resistor from the ILIM pin to AGND to program the input current limit. The relationship between the input current limit and setting resistor is: RILIM  40.5 (k) IIN _ LIM ( A ) (10) VIN  VPWIN  R6 VPWIN (12) (13) For a typical application, start with R6=5.1kΩ, R4 is 21.5kΩ. Setting the Input Voltage Regulation in Charge Mode In charge mode, connect a resistor divider from the VIN pin to AGND with tapped to REG pin to program the input voltage regulation. VIN _ R  VREG  R3  R5 R5 (14)  R5 (15) With the given R5, R3 is: R3  VIN _ R  VRGE VREG Where RILIM must exceed 20kΩ so that IIN_LIM is in the range of 0A to 2A. For a preset input voltage regulation value, say 4.75V, start with R5=5.1kΩ, R3 is 15kΩ. For most applications, use RILIM = 45kΩ (IUSB_LIM=900mA) for USB3.0, and use an RLIM = 81kΩ (IUSB_LIM=500mA) for USB2.0. NTC Function in Charge Mode Figure 12 shows that an internal resistor divider sets the low temperature threshold (VTL) and high temperature threshold (VTH) at 65%·VSYS and 35%·VSYS, respectively. For a given NTC thermistor, select an appropriate RT1 and RT2 to set the NTC window. Setting the Input Voltage Range for Different Operation Modes A resistive voltage divider from the input voltage to PWIN pin determines the operating mode of MP2633. VPWIN R6  VIN  (V) R4  R6 (11) RT2//RNTC_Cold VTL   TL  65% VSYS RT1  RT2//RNTC_Cold MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. (16) 27 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER R T2 //RNTC_Hot VTH   TH  35% (17) VSYS R T1  R T2 //RNTC_Hot Where RNTC_Hot is the value of the NTC resistor at the upper bound of its operating temperature range, and RNTC_Cold is its lower bound. The two resistors, RT1 and RT2, independently determine the upper and lower temperature limits. This flexibility allows the MP2633 to operate with most of NTC resistors for different temperature range requirements. Calculate RT1 and RT2 as follows: R T1  RT2  RNTC_Hot  RNTC_Cold  (TL  TH) TH  TL  (RNTC_Cold  RNTC_Hot ) (TL  TH)  RNTC_Cold RNTC_Hot (1 TL)  TH RNTC_Cold- (1- TH) TL  RNTC_Hot (18) (19) For example, the NCP18XH103 thermistor has the following electrical characteristic: At 0°C, RNTC_Cold = 27.445kΩ; At 50°C, RNTC_Hot = 4.1601kΩ. Based on equation (18) and equation (19), RT1=6.47kΩ and RT2 = 21.35kΩ are suitable for an NTC window between 0°C and 50°C. Chose approximate values: e.g., RT1=6.49kΩ and RT2=21.5kΩ. If no external NTC is available, connect RT1 and RT2 to keep the voltage on the NTC pin within the valid NTC window: e.g., RT1 = RT2 = 10kΩ. SYS Low Temp Threshold RT1 NTC RT2 VTL between 4.2V to 6V by the resistor divider at FB pin as R1 and R2 in the typical application circuit. VSYS  1.2V  R1  R2 R2 (20) Where 1.2V is the voltage reference of SYS. With a typical value for R2, 10kΩ, R1 can be determined by: R1  R2  VSYS  1.2V (V) 1 .2 V (21) For example, for a 5V system voltage, R2 is 10kΩ, and R1 is 31.6kΩ. Setting the Output Current Limit in Boost Mode In boost mode, connect a resistor from the OLIM pin to AGND to program the output current limit. The relationship between the output current limit and setting resistor is as follows: 70(k )  40(mV )  1.7 (22) IOLIM ( A )  RS1(m ) Where ROLIM is greater than 63.4kΩ, so IOLIM can be programmed up to 1.5A. R OLIM (k )  Selecting the Inductor Inductor selection trades off between cost, size, and efficiency. A lower inductance value corresponds with smaller size, but results in higher ripple currents, higher magnetic hysteretic losses, and higher output capacitances. However, a higher inductance value benefits from lower ripple current and smaller output filter capacitors, but results in higher inductor DC resistance (DCR) loss. Choose an inductor that does not saturate under the worst-case load condition. 1. Charge Mode V TH When MP2633 works in charge mode (as a buck converter), estimate the required inductance as: V  VBATT V (23) L  IN  BATT IL _ MAX VIN  f S Figure 12: NTC Function Block Where VIN, VBATT, and fS are the typical input RNTC High Temp Threshold Setting the System Voltage in Boost Mode In the boost mode, the system voltage can be regulated to the value customer required MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 28 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER voltage, the CC charge threshold, and the switching frequency, respectively. ∆IL_MAX is the maximum inductor ripple current, which is usually designed at 30% of the CC charge current. With a typical 5V input voltage, 30% inductor current ripple at the corner point between trickle charge and CC charge (VBATT=3V), the inductance is 1.85μH (for a 1.2MHz switching frequency), and 3.7µH (for a 600kHz switching frequency). 2. Boost Mode When the MP2633 is in boost mode (as a boost converter), the required inductance value is calculated as: L VBATT  ( VSYS  VBATT ) VSYS  fS  IL _ MAX IL _ MAX  (30%  40%)  IBATT (MAX ) IBATT (MAX )  VSYS  ISYS VBATT   noise from the device. The input capacitor impedance at the switching frequency should be less than the input source impedance to prevent high-frequency-switching current from passing to the input. For best results, use ceramic capacitors with X5R or X7R dielectrics because of their low ESR and small temperature coefficients. For most applications, a 22µF capacitor will suffice. Selecting the System Capacitor, CSYS Select CSYS based on the demand of the system current ripple. 1. Charge Mode The capacitor CSYS acts as the input capacitor of the buck converter in charge mode. The input current ripple is: (24) (25) (26) Where VBATT is the minimum battery voltage, fSW is the switching frequency, and ∆IL_MAX is the peak-to-peak inductor ripple current, which is approximately 30% of the maximum battery current, IBATT(MAX). ISYS(MAX) is the system current and η is the efficiency. In the worst case where the battery voltage is 3V, a 30% inductor current ripple, and a typical system voltage (VSYS=5V), the inductance is 1.8μH (for the 1.2MHz switching frequency) and 3.6µH (for the 600kHz switching frequency) when the efficiency is 90%. For best results, use an inductor with an inductance of 1.8μH (for the 1.2MHz switching frequency) and 3.6µH (for the 600kHz switching frequency) with a DC current rating that is at least 30% higher than the maximum charge current for applications. For higher efficiency, minimize the inductor’s DC resistance. Selecting the Input Capacitor, CIN The input capacitor CIN reduces both the surge current drawn from the input and the switching IRMS _ MAX  ISYS _ MAX  VTC  ( VIN _ MAX  VTC ) VIN _ MAX (27) Boost Mode The capacitor, CSYS, is the output capacitor of boost converter. CSYS keeps the system voltage ripple small and ensures feedback loop stability. The system current ripple is given by: 2. IRMS _ MAX  ISYS _ MAX  VTC  ( VSYS _ MAX  VTC ) (28) VSYS _ MAX Since the input voltage passes to the system directly, VIN_MAX=VSYS_MAX, both charge mode and boost mode have the same system current ripple. For ICC_MAX=2A, VTC=3V, VIN_MAX=6V, the maximum ripple current is 1A. Select the system capacitors base on the ripple-current temperature rise not exceeding 10°C. For best results, use ceramic capacitors with X5R or X7R dielectrics with low ESR and small temperature coefficients. For most applications, use a 22µF capacitor. Selecting the Battery Capacitor, CBATT CBATT is in parallel with the battery to absorb the high-frequency switching ripple current. 1. Charge Mode The capacitor CBATT is the output capacitor of the buck converter. The output voltage ripple is then: MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 29 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER rBATT 1  VBATT / VSYS VBATT   2 VBATT 8  CBATT  fS  L inductor and PGND of the IC. (29) 2. Boost Mode The capacitor CBATT is the input capacitor of the boost converter. The input voltage ripple is the same as the output voltage ripple from equation (29). Both charge mode and boost mode have the same battery voltage ripple. The capacitor CBATT can be calculated as: C BATT  1  VTC / VSYS _ MAX 2 8  rBATT _ MAX  fS  L (30) To guarantee the ±0.5% BATT voltage accuracy, the maximum BATT voltage ripple must not exceed 0.5% (e.g., 0.1%). The worst case occurs at the minimum battery voltage of the CC charge with the maximum input voltage. For VSYS_MAX=6V, VCC_MIN=VTC=3V, L=3.9µH, fS=600kHz or 1.2MHz, rBATT _ MAX  0.1% , CBATT is 2) For high-current applications, the power pads for IN, SYS, SW, BATT and PGND should be connected to as many copper planes on the board as possible. The exposed pad should connect to as many GND copper planes in the board as possible. This improves thermal performance because the board conducts heat away from the IC. 3) The PCB should have a ground plane connected directly to the return of all components through vias (e.g., two vias per capacitor for power-stage capacitors, one via per capacitor for small-signal components). If possible, add vias inside the exposed pads for the IC. A star ground design approach is typically used to keep circuit block currents isolated (power-signal/controlsignal), which reduces noise-coupling and ground-bounce issues. A single ground plane for this design gives good results. 4) Place ISET, OLIM and ILIM resistors very close to their respective IC pins. 22µF (for a 600kHz switching frequency) or 10µF (for a 1.2MHz switching frequency). A 22µF ceramic with X5R or X7R dielectrics capacitor in parallel with a 220uF electrolytic capacitor will suffice. PCB LAYOUT GUIDE PCB layout is very important to meet specified noise, efficiency and stability requirements. The following design considerations can improve circuit performance: Top Layer 1) Route the power stage adjacent to their grounds. Aim to minimize the high-side switching node (SW, inductor) trace lengths in the highcurrent paths and the current sense resistor trace. Keep the switching node short and away from all small control signals, especially the feedback network. Place the input capacitor as close as possible to the VIN and PGND pins. The local power input capacitors, connected from the SYS to PGND, must be placed as close as possible to the IC. Bottom Layer Figure 13: PCB Layout Guide Place the output inductor close to the IC and connect the output capacitor between the MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 30 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER DESIGN EXAMPLE Below is a design example following the application guidelines for the specifications: Table 3: Design Example VIN VOUT fSW 5V 3.7V 1200kHz Figure14 shows the detailed application schematic. The Typical Performance Characteristics section shows the typical performance and circuit waveforms. For more possible applications of this device, please refer to the related Evaluation Board datasheets. MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 31 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER TYPICAL APPLICATION CIRCUITS Figure14: Detailed Application Circuit MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 32 MP2633 – 1.5A SINGLE CELL SWITCH MODE BATTERY CHARGER PACKAGE INFORMATION QFN24 (4x4mm) 3.90 4.10 2.50 2.80 19 PIN 1 ID MARKING 18 3.90 4.10 PIN 1 ID INDEX AREA PIN 1 ID SEE DETAIL A 24 1 0.50 BSC 2.50 2.80 0.18 0.30 6 13 0.35 0.45 TOP VIEW 12 7 BOTTOM VIEW PIN 1 ID OPTION A 0.30x45º TYP. PIN 1 ID OPTION B R0.25 TYP. 0.80 1.00 0.20 REF 0.00 0.05 DETAIL A SIDE VIEW 3.90 2.70 0.70 0.25 NOTE: 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH. 3) LEAD COPLANARITY SHALL BE0.10 MILLIMETER MAX. 4) DRAWING CONFIRMS TO JEDEC MO-220, VARIATION VGGD. 5) DRAWING IS NOT TO SCALE. 0.50 RECOMMENDED LAND PATTERN NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP2633 Rev. 1.08 www.MonolithicPower.com 4/27/2016 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2016 MPS. All Rights Reserved. 33