SLUSAK9B September   2011  – April 2015

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Adapter Detect and ACOK Output
      2. 9.3.2  Adapter Overvoltage (ACOVP)
      3. 9.3.3  System Power Selection
      4. 9.3.4  Automatic Internal Soft-Start Charger Current
      5. 9.3.5  Converter Operation
      6. 9.3.6  Input Overcurrent Protection (ACOC)
      7. 9.3.7  Charge Overcurrent Protection (CHGOCP)
      8. 9.3.8  Battery Overvoltage Protection (BATOVP)
      9. 9.3.9  Battery Shorted to Ground (BATLOWV)
      10. 9.3.10 Thermal Shutdown Protection (TSHUT)
      11. 9.3.11 Inductor Short, MOSFET Short Protection
    4. 9.4 Device Functional Modes
      1. 9.4.1 Enable and Disable Charging
      2. 9.4.2 Continuous Conduction Mode (CCM)
      3. 9.4.3 Discontinuous Conduction Mode (DCM)
    5. 9.5 Programming
      1. 9.5.1 SMBus Interface
      2. 9.5.2 Battery LEARN Cycle
      3. 9.5.3 Charge Time-out
      4. 9.5.4 High-Accuracy Current-Sense Amplifier
      5. 9.5.5 EMI Switching Frequency Adjust
    6. 9.6 Register Maps
      1. 9.6.1 Battery-Charger Commands
      2. 9.6.2 Setting Charger Options
      3. 9.6.3 Charge Options Register [reset = 0x12H]
      4. 9.6.4 Setting the Charge Current
      5. 9.6.5 Setting the Charge Voltage
      6. 9.6.6 Setting Input Current
      7. 9.6.7 Support Turbo Boost Function
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Negative Output Voltage Protection
        2. 10.2.2.2 Reverse Input Voltage Protection
        3. 10.2.2.3 Reduce Battery Quiescent Current
        4. 10.2.2.4 Inductor Selection
        5. 10.2.2.5 Input Capacitor
        6. 10.2.2.6 Output Capacitor
        7. 10.2.2.7 Power MOSFETs Selection
        8. 10.2.2.8 Input Filter Design
        9. 10.2.2.9 bq24735 Design Guideline
      3. 10.2.3 Application Curves
    3. 10.3 System Examples
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Device Support
      1. 13.1.1 Third-Party Products Disclaimer
    2. 13.2 Documentation Support
      1. 13.2.1 Related Documentation
    3. 13.3 Trademarks
    4. 13.4 Electrostatic Discharge Caution
    5. 13.5 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted) (1)
MIN MAX UNIT
Voltage SRN, SRP, ACN, ACP, CMSRC, VCC –0.3 30 V
PHASE –2 30
ACDET, SDA, SCL, LODRV, REGN, IOUT, ILIM, ACOK –0.3 7
BTST, HIDRV, ACDRV, BATDRV –0.3 36
LODRV (2% duty cycle) –4 7
HIDVR (2% duty cycle) –4 36
PHASE (2% duty cycle) –4 30
Maximum difference voltage SRP–SRN, ACP–ACN –0.5 0.5
Junction temperature, TJ –40 155 °C
Storage temperature, Tstg –55 155 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Charged device model (CDM), per JEDEC specification JESD22-C101(2) ±500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
Voltage SRN, SRP, ACN, ACP, CMSRC, VCC 0 24 V
PHASE –2 24
ACDET, SDA, SCL, LODRV, REGN, IOUT, ILIM, ACOK 0 6.5
BTST, HIDRV, ACDRV, BATDRV 0 30
Maximum difference voltage SRP–SRN, ACP–ACN –0.2 0.2 V
Junction temperature, TJ 0 125 °C

7.4 Thermal Information

THERMAL METRIC(1) bq24735 UNIT
RGR [VQFN]
20 PINS
RθJA Junction-to-ambient thermal resistance 46.8 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 56.9 °C/W
RθJB Junction-to-board thermal resistance 46.6 °C/W
ψJT Junction-to-top characterization parameter 0.6 °C/W
ψJB Junction-to-board characterization parameter 15.3 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 4.4 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.

7.5 Electrical Characteristics

4.5 V ≤ VVCC ≤ 24 V, 0°C ≤ TJ ≤ 125°C, typical values are at TA = 25°C, with respect to GND (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
OPERATING CONDITIONS
VVCC_OP VCC Input voltage operating range 4.5 24 V
CHARGE VOLTAGE REGULATION
VBAT_REG_RNG Battery voltage range 1.024 19.2 V
VBAT_REG_ACC Charge voltage regulation accuracy ChargeVoltage() = 0x41A0H 16.716 16.8 16.884 V
–0.5% 0.5%
ChargeVoltage() = 0x3130H 12.529 12.592 12.655 V
–0.5% 0.5%
ChargeVoltage() = 0x20D0H 8.35 8.4 8.45 V
–0.6% 0.6%
ChargeVoltage() = 0x1060H 4.163 4.192 4.221 V
–0.7% 0.7%
CHARGE CURRENT REGULATION
VIREG_CHG_RNG Charge current regulation differential voltage range VIREG_CHG = VSRP - VSRN 0 81.28 mV
ICHRG_REG_ACC Charge current regulation accuracy 10-mΩ current-sensing resistor ChargeCurrent() = 0x1000H 3973 4096 4219 mA
–3% 3%
ChargeCurrent() = 0x0800H 1946 2048 2150 mA
–5% 5%
ChargeCurrent() = 0x0200H 410 512 614 mA
–20% 20%
ChargeCurrent() = 0x0100H 172 256 340 mA
–33% 33%
ChargeCurrent() = 0x0080H 64 128 192 mA
–50% 50%
INPUT CURRENT REGULATION
VIREG_DPM_RNG Input current regulation differential voltage range VIREG_DPM = VACP – VACN 0 80.64 mV
IDPM_REG_ACC Input current regulation accuracy 10-mΩ current-sensing resistor InputCurrent() = 0x1000H 3973 4096 4219 mA
–3% 3%
InputCurrent() = 0x0800H 1946 2048 2150 mA
–5% 5%
InputCurrent() = 0x0400H 870 1024 1178 mA
–15% 15%
InputCurrent() = 0x0200H 384 512 640 mA
–25% 25%
INPUT CURRENT OR CHARGE CURRENT-SENSE AMPLIFIER
VACP/N_OP Input common-mode range Voltage on ACP/ACN 4.5 24 V
VSRP/N_OP Output common-mode range Voltage on SRP/SRN 0 19.2 V
VIOUT IOUT output voltage range 0 3.3 V
IIOUT IOUT output current 0 1 mA
AIOUT Current-sense amplifier gain V(ICOUT)/V(SRP-SRN) or V(ACP-ACN) 20 V/V
VIOUT_ACC Current-sense output accuracy V(SRP-SRN) or V(ACP-ACN) = 40.96 mV –2% 2%
V(SRP-SRN) or V(ACP-ACN) = 20.48 mV –4% 4%
V(SRP-SRN) or V(ACP-ACN) = 10.24 mV –15% 15%
V(SRP-SRN) or V(ACP-ACN) = 5.12 mV –20% 20%
V(SRP-SRN) or V(ACP-ACN) = 2.56 mV –33% 33%
V(SRP-SRN) or V(ACP-ACN) = 1.28 mV –50% 50%
CIOUT_MAX Maximum output load capacitance For stability with 0- to 1-mA load 100 pF
REGN REGULATOR
VREGN_REG REGN regulator voltage VVCC > 6.5 V, VACDET > 0.6 V (0-45 mA load) 5.5 6 6.5 V
IREGN_LIM REGN current limit VREGN = 0 V, VVCC > UVLO charge enabled and not in TSHUT 50 75 mA
VREGN = 0 V, VVCC > UVLO charge disabled or in TSHUT 7 14 mA
CREGN REGN output capacitor required for stability ILOAD = 100 µA to 50 mA 1 µF
INPUT UNDERVOLTAGE LOCKOUT COMPARATOR (UVLO)
UVLO Undervoltage rising threshold VVCC rising 3.5 3.75 4 V
Undervoltage hysteresis, falling VVCC falling 340 mV
FAST DPM COMPARATOR (FAST_DPM)
VFAST_DPM Fast DPM comparator stop charging rising threshold with respect to input current limit, voltage across input sense resistor rising edge 103% 107% 111%
QUIESCENT CURRENT
IBAT_BATFET_OFF Battery BATFET OFF STATE Current, BATFET off,
ISRP + ISRN + IPHASE + IACP + IACN 		VVBAT = 16.8 V, VCC disconnect from battery, BATFET charge pump off, BATFET turns off, TJ = 0 to 85°C 5 µA
IBAT_BATFET_ON Battery BATFET ON STATE Current, BATFET on,
ISRP + ISRN + IPHASE + IVCC + IACP + IACN 		VVBAT = 16.8 V, VCC connect from battery, BATFET charge pump on, BATFET turns on, TJ = 0 to 85°C 25 µA
ISTANDBY Standby quiescent current, IVCC + IACP + IACN VVCC > UVLO, VACDET > 0.6 V, charge disabled,
TJ = 0 to 85°C		 0.65 0.8 mA
IAC_NOSW Adapter bias current during charge,
IVCC + IACP + IACN 		VVCC > UVLO, 2.4 V < VACDET < 3.15 V,
charge enabled, no switching, TJ = 0 to 85°C		 1.5 3 mA
IAC_SW Adapter bias current during charge,
IVCC + IACP + IACN		 VVCC > UVLO, 2.4 V < VACDET < 3.15 V,
charge enabled, switching, MOSFET Sis412DN		 10 mA
ACOK COMPARATOR
VACOK_RISE ACOK rising threshold VVCC > UVLO, VACDET rising 2.376 2.4 2.424 V
VACOK_FALL_HYS ACOK falling hysteresis VVCC> UVLO, VACDET falling 35 55 75 mV
VWAKEUP_RISE WAKEUP detect rising threshold VVCC> UVLO, VACDET rising 0.57 0.8 V
VWAKEUP_FALL WAKEUP detect falling threshold VVCC> UVLO, VACDET falling 0.3 0.51 V
VCC to SRN COMPARATOR (VCC_SRN)
VVCC-SRN_FALL VCC-SRN falling threshold VVCC falling toward VSRN 70 125 200 mV
VVCC-SRN _RHYS VCC-SRN rising hysteresis VVCC rising above VSRN 100 150 200 mV
ACN to SRN COMPARATOR (ACN_SRN)
VACN-SRN_FALL ACN to BAT falling threshold VACN falling toward VSRN 120 200 280 mV
VACN-SRN_RHYS ACN to BAT rising hysteresis VACN rising above VSRN 40 80 120 mV
HIGH-SIDE IFAULT COMPARATOR (IFAULT_HI)(1)
VIFAULT_HI_RISE ACP to PHASE rising threshold ChargeOption() bit [8] = 1 (Default) 450 750 1200 mV
ChargeOption() bit [8] = 0 Disable function
LOW-SIDE IFAULT COMPARATOR (IFAULT_LOW)(1)
VIFAULT_LOW_RISE PHASE to GND rising threshold ChargeOption() bit [7] = 0 (Default) 70 135 220 mV
ChargeOption() bit [7] = 1 140 230 340
INPUT OVERVOLTAGE COMPARATOR (ACOV)
VACOV ACDET overvoltage rising threshold VACDET rising 3.05 3.15 3.25 V
VACOV_HYS ACDET overvoltage falling hysteresis VACDET falling 50 75 100 mV
INPUT OVERCURRENT COMPARATOR (ACOC)(1)
VACOC Adapter overcurrent rising threshold with respect to input current limit, voltage across input sense resistor rising edge ChargeOption() bit [1] = 1 (Default) 300% 333% 366%
ChargeOption() bit [1] = 0 Disable function
VACOC_min Min ACOC threshold clamp voltage ChargeOption() bit [1] = 1 (333%),
InputCurrent () = 0x0400H (10.24 mV)		 40 45 50 mV
VACOC_max Max ACOC threshold clamp voltage ChargeOption() bit [1] = 1 (333%),
InputCurrent () = 0x1F80H (80.64 mV)		 135 150 165 mV
BAT OVERVOLTAGE COMPARATOR (BAT_OVP)
VOVP_RISE Overvoltage rising threshold as percentage of VBAT_REG VSRN rising 103% 104% 106%
VOVP_FALL Overvoltage falling threshold as percentage of VBAT_REG VSRN falling 102%
CHARGE OVERCURRENT COMPARATOR (CHG_OCP)
VOCP_RISE Charge overcurrent rising threshold, measure voltage drop across current-sensing resistor ChargeCurrent() = 0x0xxxH 54 60 66 mV
ChargeCurrent() = 0x1000H – 0x17C0H 80 90 100
ChargeCurrent() = 0x1800 H– 0x1FC0H 110 120 130
CHARGE UNDERCURRENT COMPARATOR (CHG_UCP)
VUCP_FALL Charge undercurrent falling threshold VSRP falling toward VSRN 1 5 9 mV
LIGHT LOAD COMPARATOR (LIGHT_LOAD)
VLL_FALL Light load falling threshold Measure the voltage drop across current-sensing resistor 1.25 mV
VLL_RISE_HYST Light load rising hysteresis 1.25 mV
BATTERY DEPLETION COMPARATOR (BAT_DEPL) [1]
VBATDEPL_FALL Battery depletion falling threshold, percentage of voltage regulation limit, VSRN falling ChargeOption() bit [12:11] = 00 55.53% 59.19% 63.5%
ChargeOption() bit [12:11] = 01 58.68% 62.65% 67.5%
ChargeOption() bit [12:11] = 10 62.17% 66.55% 71.5%
ChargeOption() bit [12:11] = 11 (Default) 66.06% 70.97% 77%
VBATDEPL_RHYST Battery depletion rising hysteresis, VSRN rising ChargeOption() bit [12:11] = 00 225 305 400 mV
ChargeOption() bit [12:11] = 01 240 325 430
ChargeOption() bit [12:11] = 10 255 345 450
ChargeOption() bit [12:11] = 11 (Default) 280 370 490
tBATDEPL_RDEG Battery depletion rising deglitch (specified by design) Delay to turn off ACFET and turn on BATFET during LEARN cycle 600 ms
BATTERY LOWV COMPARATOR (BAT_LOWV)
VBATLV_FALL Battery LOWV falling threshold VSRN falling 2.4 2.5 2.6 V
VBATLV_RHYST Battery LOWV rising hysteresis VSRN rising 200 mV
IBATLV Battery LOWV charge current limit 10-mΩ current-sensing resistor 0.5 A
THERMAL SHUTDOWN COMPARATOR (TSHUT)
TSHUT Thermal shutdown rising temperature Temperature rising 155 °C
TSHUT_HYS Thermal shutdown hysteresis, falling Temperature falling 20 °C
ILIM COMPARATOR
VILIM_FALL ILIM as CE falling threshold VILIM falling 60 75 90 mV
VILIM_RISE ILIM as CE rising threshold VILIM rising 90 105 120 mV
LOGIC INPUT (SDA, SCL)
VIN_ LO Input low threshold 0.8 V
VIN_ HI Input high threshold 2.1 V
IIN_ LEAK Input bias current V = 7 V –1 1 μA
LOGIC OUTPUT OPEN DRAIN (ACOK, SDA)
VOUT_ LO Output saturation voltage 5-mA drain current 500 mV
IOUT_ LEAK Leakage current V = 7 V –1 1 μA
ANALOG INPUT (ACDET, ILIM)
IIN_ LEAK Input bias current V = 7 V –1 1 μA
PWM OSCILLATOR
FSW PWM switching frequency ChargeOption() bit [9] = 0 (Default) 600 750 900 kHz
FSW+ PWM increase frequency ChargeOption() bit [10:9] = 11 665 885 1100 kHz
FSW– PWM decrease frequency ChargeOption() bit [10:9] = 01 465 615 765 kHz
BATFET GATE DRIVER (BATDRV)
IBATFET BATDRV charge pump current limit 40 60 µA
VBATFET Gate drive voltage on BATFET VBATDRV – VSRN when VSRN > UVLO 5.5 6.1 6.5 V
RBATDRV_LOAD Minimum load resistance between BATDRV and SRN 500 kΩ
RBATDRV_OFF BATDRV turnoff resistance I = 30 µA 5 6.2 7.4 kΩ
ACFET GATE DRIVER (ACDRV)
IACFET ACDRV charge pump current limit 40 60 μA
VACFET Gate drive voltage on ACFET VACDRV – VCMSRC when VVCC > UVLO 5.5 6.1 6.5 V
RACDRV_LOAD Minimum load resistance between ACDRV and CMSRC 500 kΩ
RACDRV_OFF ACDRV turnoff resistance I = 30 µA 5 6.2 7.4 kΩ
VACFET_LOW ACDRV turnoff when Vgs voltage is low (specified by design) 5.9 V
PWM HIGH-SIDE DRIVER (HIDRV)
RDS_HI_ON High-side driver turnon resistance VBTST – VPH = 5.5 V, I = 10 mA 6 10 Ω
RDS_HI_OFF High-side driver turnoff resistance VBTST – VPH = 5.5 V, I = 10 mA 0.65 1.3 Ω
VBTST_REFRESH Bootstrap refresh comparator threshold voltage VBTST – VPH when low-side refresh pulse is requested 3.85 4.3 4.7 V
PWM LOW-SIDE DRIVER (LODRV)
RDS_LO_ON Low-side driver turnon resistance VREGN = 6 V, I = 10 mA 7.5 12 Ω
RDS_LO_OFF Low-side driver turnoff resistance VREGN = 6 V, I = 10 mA 0.9 1.4 Ω
INTERNAL SOFT START
ISTEP Soft start current step In CCM mode 10-mΩ current-sensing resistor 64 mA
(1) User can adjust threshold through SMBus ChargeOption() REG0x12.

7.6 Timing Requirements

MIN TYP MAX UNIT
ACOK COMPARATOR
VACOK_RISE_DEG ACOK rising deglitch (specified by design) VVCC > UVLO, VACDET rising above 2.4 V,
First time OR ChargeOption() bit [15] = 0 		100 150 200 ms
VVCC > UVLO, VACDET rising above 2.4 V,
(NOT First time) AND ChargeOption() bit [15] = 1 (Default)		 0.9 1.3 1.7 s
INPUT OVERCURRENT COMPARATOR (ACOC)(1)
tACOC_DEG ACOC deglitch time (specified by design) Voltage across input sense resistor rising to disable charge 2.3 4.2 6.6 ms
BATTERY DEPLETION COMPARATOR (BAT_DEPL) [1]
tBATDEPL_RDEG Battery depletion rising deglitch (specified by design) Delay to turn off ACFET and turn on BATFET during LEARN cycle 600 ms
PWM DRIVER TIMING
tLOW_HIGH Driver dead time from low side to high side 20 ns
tHIGH_LOW Driver dead time from high side to low side 20 ns
INTERNAL SOFT START
tSTEP Soft start current step time 240 μs
SMBus TIMING CHARACTERISTICS
tR SCLK/SDATA rise time 1 μs
tF SCLK/SDATA fall time 300 ns
tW(H) SCLK pulse width high 4 50 μs
tW(L) SCLK Pulse Width Low 4.7 μs
tSU(STA) Setup time for START condition 4.7 μs
tH(STA) START condition hold time after which first clock pulse is generated 4 μs
tSU(DAT) Data setup time 250 ns
tH(DAT) Data hold time 300 ns
tSU(STOP) Setup time for STOP condition 4 µs
t(BUF) Bus free time between START and STOP condition 4.7 μs
FS(CL) Clock Frequency 10 100 kHz
HOST COMMUNICATION FAILURE
ttimeout SMBus bus release time-out(2) 25 35 ms
tBOOT Deglitch for watchdog reset signal 10 ms
tWDI Watchdog time-out period, ChargeOption() bit [14:13] = 01(3) 35 44 53 s
Watchdog time-out period, ChargeOption() bit [14:13] = 10(3) 70 88 105 s
Watchdog time-out period, ChargeOption() bit [14:13] = 11(3) (Default) 140 175 210 s
(1) User can adjust threshold through SMBus ChargeOption() REG0x12.
(2) Devices participating in a transfer will time out when any clock low exceeds the 25-ms minimum time-out period. Devices that have detected a time-out condition must reset the communication no later than the 35-ms maximum time-out period. Both a master and a slave must adhere to the maximum value specified, as it incorporates the cumulative stretch limit for both a master (10 ms) and a slave (25 ms).
(3) User can adjust threshold through SMBus ChargeOption() REG0x12.

7.7 Typical Characteristics

bq24735 tc1_lus702.png
CH1: VCC, 10 V/div, CH2: ACDET, 2 V/div, CH3: ACOK, 5 V/div,
CH4: REGN, 5 V/div, 40 ms/div
Figure 1. VCC, ACDET, REGN and ACOK Power Up
bq24735 tc3_lus702.png
CH1: Vin, 10 V/div, CH2: LODRV, 5 V/div,
CH3: PHASE, 10 V/div,
CH4: inductor current, 2 A/div, 2 ms/div
Figure 3. Current Soft-Start
bq24735 tc5_lusa79.png
CH1: PHASE, 10 V/div, CH2: LODRV, 5 V/div,
CH3: HIDRV, 10 V/div
CH4: inductor current, 2 A/div, 400 ns/div
Figure 5. Continuous Conduction Mode Switching Waveforms
bq24735 tc_pulse_lusak9.png
CH1: PHASE, 10 V/div, CH2: LODRV, 5 V/div,
CH4: inductor current, 2 A/div, 4 µs/div
Figure 7. 100% Duty and Refresh Pulse
bq24735 buck_to_boost_lusak9.png
CH3: adapter current, 2 A/div,
CH4: battery current, 2 A/div, 10 ms/div
Figure 9. Buck-to-Boost Mode
bq24735 tc2_lus702.png
CH1: ILIM, 1 V/div, CH4: inductor current, 1 A/div, 20 ms/div
Figure 2. Charge Enable by ILIM
bq24735 tc4_lus702.png
CH1: ILIM, 1 V/div, CH4: inductor current, 1 A/div, 4 µs/div
Figure 4. Charge Disable by ILIM
bq24735 tc6_lus702.png
CH1: PHASE, 10 V/div, CH2: LODRV, 5 V/div,
CH3: HIDRV, 10 V/div,
CH4: inductor current, 1 A/div, 400 ns/div
Figure 6. Cycle-by-Cycle Synchronous to Nonsynchronous
bq24735 tc_load_lusak9.png
CH2: battery current, 2 A/div, CH3: adapter current, 2 A/div,
CH4: system load current, 2 A/div, 100 µs/div
Figure 8. System Load Transient (Input DPM)
bq24735 boost_to_buck_lusak9.png
CH3: adapter current, 2 A/div,
CH4: battery current, 2 A/div, 10 ms/div
Figure 10. Boost-to-Buck Mode