LTC2952 Pushbutton PowerPath Controller with Supervisor FEATURES DESCRIPTION n The LTC®2952 is a power management device that features three main functions: pushbutton on/off control of system power, ideal diode PowerPath™ controllers and system monitoring. The LTC2952’s pushbutton input, which provides on/off control of system power, has independently adjustable ON and OFF debounce times.
LTC2952 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2) Supply Voltages V1, V2, VS .............................................. –0.3V to 30V Input Voltages PB .................................... –6V to MAX (V1, V2, VS) V ONT, OFFT ............................................... –0.3V to 3V M1, M2, PFI, VM, WDE, KILL ................... –0.3V to 7V Output Voltages G1, G2, EN .................... –0.3V to MAX (V1, V2, VS) V G1STAT, PFO, RST, INT ............................ –0.3V to 7V Input Currents PB .........
LTC2952 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V1 = V2 = VS = 2.7V to 28V unless otherwise noted. (Notes 2, 3) SYMBOL PARAMETER CONDITIONS VMAX Operating Supply Voltage V1, V2 or VS l V1 = 2.7V to 28V, V2 = 0V, VS = Open or V2 = 2.7V to 28V, V1 = 0V, VS = Open. Measured Current at V1 or V2. l V1 = 2.7V to 28V, V2 = 3.5V, VS = Open. Measured Current at V1.
LTC2952 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V1 = V2 = VS = 2.7V TO 28V unless otherwise noted. (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Debounce Time Pins (ONT, OFFT) IONT,OFFT ONT/OFFT Pull-Up/Pull-Down Current When Timer Is Active VONT, VOFFT = 0V (Pull-Up), VONT, VOFFT = 1.5V (Pull-Down) l ±1.6 ±2.0 ±2.
LTC2952 ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V1 = V2 = VS = 2.7V to 28V unless otherwise noted.
LTC2952 TIMING DIAGRAMS Ideal Diode Function – Gate Turn-On and Turn-Off Time 12.2V 12.2V 12V VS 11.8V 12V 12.05V 12.05V 9V VGX VX = 12V 10.5V 5.3V 2952 TD01 tG(ON) tG(OFF) Pushbutton Debounce Times, KILL Wait Time and Enable Lockout Time with KILL Above Threshold PB 0.775V EN 0.5*VPULL-UP INT tDB,ON 0.5*VPULL-UP tONT t < tOFFT tDB,OFF tOFFT t > tONT tKILL, OFF WAIT tDB,OFF tDB,ON tINT(MIN) tEN, LOCKOUT 2952 TD02 KILL On Blanking with KILL Below Threshold KILL EN 0.
LTC2952 TIMING DIAGRAMS PFI and PFO PFI 0.515V 0.500V PFO 0.5*VPULL-UP 0.5*VPULL-UP tPFI tPFI 2952 TD04 WDE Minimum Pulse Width WDE tWDE(PW MIN) 2952 TD05 VM, WDE and RST VM WDE DON'T CARE DON'T CARE DON'T CARE DON'T CARE RST tRST 200ms tWDE 1.6s tRST 200ms
LTC2952 TYPICAL PERFORMANCE CHARACTERISTICS IIN-OFF vs Input Supply Voltage at Different Temperatures 110 3.5 V1 = VS = VIN, V2 = 0V OR V2 = VS = VIN, V1 = 0V 130°C 100 130°C 90°C 30 –45°C –60°C IIN_ON (μA) 25°C 25°C 80 70 –45°C 60 20 10 20 25 5 15 INPUT SUPPLY VOLTAGE VIN (V) 3.3 3.2 –60°C 3.1 V1 = VIN, V2 = 0, VS = OPEN OR V2 = VIN, V1 = 0,VS = OPEN M1 = OPEN, M2 = 0V 0 V1 = 28V, VS = OPEN 3.
LTC2952 TYPICAL PERFORMANCE CHARACTERISTICS KILL On Blanking, KILL Wait Time, Enable Lockout Time vs Temperature at Different Input Voltages Typical Transient Duration vs Comparator Overdrive (VM, KILL, PFI, M1 and M2) 1 COMPARATOR TRIPS ABOVE CURVE 0.1 0.1 1 10 100 Reset Timeout Period vs Temperature at Different Input Voltages 260 480 240 440 V1 = V2 = VS = 28V 220 tRST (ms) tKILL, ON BLANK/tKILL, OFFWAIT/tEN, LOCKOUT (ms) TYPICAL TRANSIENT DURATION (ms) 10 0.01 0.
LTC2952 PIN FUNCTIONS (TSSOP/QFN) EN (Pin 14/Pin 11): DC/DC Enable Output. This pin is a high voltage open-drain pull-down used to control system power. EN pin goes high impedance after an initial turn-on command (via either the digital on or a valid pushbutton on—refer to the Applications Information section). EN pin pulls low at the end of a valid power-down sequence, or when KILL pin is driven low anytime after a valid power-up sequence.
LTC2952 PIN FUNCTIONS (TSSOP/QFN) PB (Pin 7/Pin 4): Pushbutton Input. Input to a comparator with 0.775V falling threshold and 25mV hysteresis. PB has a 10μA internal pull-up to an internal supply (4V). This pin provides on/off power supply control via the EN pin, which is typically connected to an external DC/DC converter. Setting the PB pin low for a time determined by the ONT timing capacitor toggles the EN pin high impedance.
LTC2952 BLOCK DIAGRAM SECONDARY SUPPLY TO LOAD V2 PRIMARY SUPPLY V1 VS IDEAL DIODE DRIVER 2 VIN V2 VS VS V1 + – A2 GATE G2 LINEAR GATE DRIVER AND VOLTAGE CLAMP ANALOG CONTROLLER VS IDEAL DIODE DRIVER 1 VIN + – A1 LDO/BAND GAP LINEAR GATE GATE DRIVER AND VOLTAGE CLAMP STAT ON/OFF ANALOG CONTROLLER REF G1 G1STAT VCC 0.5V 0.775V – INTERNAL ENABLE CP4 CP5 – INTERNAL ENABLE KILL PUSHBUTTON DETECT CP3 10μA 3μA LOGIC CP6 PB + M1 + – 0.775V 0.5V – VCC + 0.
LTC2952 OPERATION The LTC2952 is designed to simplify applications requiring management of multiple power sources. The three main features of the part are: pushbutton control, ideal diode PowerPath controllers and system monitoring. The Block Diagram on the previous page shows the part divided into its main functional blocks. RST and PFI, PFO pins. The voltage monitoring (VM) and the watchdog (WDE) input pins determine the state of the RST output with 200ms reset time and 1.6s watchdog time.
LTC2952 OPERATION DC2 DC2 IDEAL DIODE 2 IDEAL DIODE 2 DC/DC SHDN DC1 DC1 IDEAL DIODE 1 V2 DC/DC SHDN IDEAL DIODE 1 V1 V2 V1 G1 – IDEAL DIODE DRIVER 1 M2 + + – PB 0.
LTC2952 APPLICATIONS INFORMATION The LTC2952 is a versatile power management IC with pushbutton on/off control and system supervisory features. The power management function features ideal diode PowerPath control that provides low loss switchover between two DC sources. This PowerPath control behavior is configurable to satisfy various application requirements.
LTC2952 APPLICATIONS INFORMATION pin of a DC/DC converter. The PB input achieves PowerPath control by toggling this EN pin. Note that in this application both of the ideal diodes are enabled all the time, therefore either Q1 or Q2 can be replaced by Schottky diodes as long as the voltage drop across the Schottky diodes and their reverse leakage currents are acceptable.
LTC2952 APPLICATIONS INFORMATION WALL ADAPTER Q2 TO SYSTEM BATTERY DC/DC Q1 G2 SHDN G1 VS V1 V2 M1 R9 LTC2952 EN * M2 C2 R10 PB S1 *EXTERNAL PULL-UP REQUIRED 2952 F06 Figure 6. PowerPath Configuration D (0.515V), both of the ideal diode drivers and the DC/DC converter are enabled. Thus, power is delivered to the system. As soon as the wall adapter voltage falls below its trip threshold, a shutdown sequence is immediately started.
LTC2952 APPLICATIONS INFORMATION VALID PB ‘TURN-ON’ EVENT VALID PB ‘TURN-OFF’ EVENT INVALID PB RELEASE EVENT INVALID PB PUSH EVENT INVALID PB PUSH EVENT PB ONT CAP OFFT CAP INTERNAL ON/OFF SIGNAL INT tDB,ON 26ms tONT tDB 26ms tDB,OFF 26ms tOFFT tDB 26ms
LTC2952 APPLICATIONS INFORMATION Accurate Comparator Input Pins VM, PFI, KILL, M1 and M2 VTRIP VM, PFI, KILL, M1 and M2 are high impedance input pins to accurate comparators with a falling threshold of 0.500V. Note the following differences between some of these pins: the VM pin comparator has no hysteresis while the other comparators have 15mV hysteresis and the M1 pin has a 3μA pull-up current while the other input pins do not. R1 1% + PIN R2 1% – + – 0.
LTC2952 APPLICATIONS INFORMATION WDE pin. The watchdog timer can expire due to any of the following conditions: 1. No valid edge on the WDE pin in a tWDE (1.6s) time period after the RST pin transitions from pulling low to high impedance. 2. No valid edge on the WDE pin in a tWDE (1.6s) time period since the last valid edge on the WDE pin while the RST pin is high impedance. As shown in the Timing Diagrams section, when the watchdog timer is allowed to expire while voltage at the VM pin is higher than 0.
LTC2952 APPLICATIONS INFORMATION Aborted Power-On Sequence Extended Power During Turn-Off The power-on sequence is aborted when the μP fails to set the KILL pin high before the 400ms KILL On Blanking time expires, as shown in the timing diagram in Figure 11. When the KILL On Blanking timer expires (t7), the KILL pin is still low indicating that the μP/system has failed to power on successfully.
LTC2952 APPLICATIONS INFORMATION Setting Up Different Configurations The various configurations discussed previously are summarized in Table 2, including the ideal diode PowerPath state (ID1-primary, ID2-secondary). Note that an input above 0.515V (typical rising threshold) on the M1 and M2 pins is indicated with a 1 and an input below 0.500V (typical falling threshold) is represented by a 0. Also, an enabled ideal diode driver is indicated with a 1 and a disabled driver is indicated with a 0. Table 2.
LTC2952 APPLICATIONS INFORMATION MODE 0 M1 = 0 M2 = 0 EN = 0 G1 = ON G2 = ON VALID PB VALID PB MODE 1 M1 = 0 M2 = 0 EN = 1 G1 = ON G2 = ON M1 M1 M1 M1 M2 M2 M2 PB CONTROL OF EN PIN M2 DIGITAL OFF COMMAND MODE 2 M1 = 0 M2 = 1 EN = 0 G1 = OFF G2 = ON VALID PB VALID PB MODE 4 M1 = 1 M2 = 0 EN = 0 G1 = OFF G2 = OFF (PB IGNORE) M1 M1 M2 MODE 6 M1 = 1 M2 = 1 EN = 0 G1 = OFF G2 = OFF MODE 3 M1 = 0 M2 = 1 EN = 1 G1 = OFF G2 = ON MODE 5 M1 = 1 M2 = 0 EN = 1 G1 = OFF G2 = OFF (PB IGNORE) M2 DIGIT
LTC2952 TYPICAL APPLICATIONS Wall Adapter and Battery Automatic Load Switchover with Simple On/Off Pushbutton Control and Voltage Monitors for System Power without μP WALL ADAPTER 5V TO 20V 2.5V Q1 Si7913DN R6 1k LT1767-2.5 SHDN** G1 R1 365k R8 10k R4 100k VS PFI G2 V1 EN V2 VM R7 1k POWER LOW INDICATOR R3 511k 4.
LTC2952 TYPICAL APPLICATIONS Uninterruptible Power Supply with Preferential Wall Adapter Operation and Automatic Load Switchover to Battery with Pushbutton Control, Voltage Monitors and Watchdog WALL ADAPTER 5V TO 30V 3.3V VIN Q2 Si7421DN CVS 0.1μF Si7941DP VOUT LTC1625 R6 10k RUN/SS** Q1 5V TO 30V BATTERY R3 1.
LTC2952 TYPICAL APPLICATIONS Critical System with Primary Supply and Temporary Battery Backup with Pushbutton Control, Voltage Monitors and Watchdog PRIMARY POWER 12V TO 30V 3.3V VIN Q1 SUB75P03-07 Q2 SUB75P03-07 VOUT LTC3728 R6 10k RUN/SS** R3 1.82M 12V BATTERY R9 2.15M R10 100k G2 PFI V1 EN V2 VM LTC2952 R8 10k R4 100k VS G1 R7 10k R1 511k R5 10k R2 100k RST M1 INT M2 G1STAT μP PFO C2 0.
LTC2952 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. F Package 20-Lead Plastic TSSOP (4.4mm) (Reference LTC DWG # 05-08-1650) 6.40 – 6.60* (.252 – .260) 1.05 ±0.10 6.60 ±0.10 20 19 18 17 16 15 14 13 12 11 4.50 ±0.10 0.45 ±0.05 6.40 (.252) BSC 0.65 BSC 1 2 3 4 5 6 7 8 9 10 RECOMMENDED SOLDER PAD LAYOUT 4.30 – 4.50** (.169 – .177) 0.09 – 0.20 (.0035 – .0079) 0.25 REF 1.10 (.0433) MAX 0° – 8° 0.50 – 0.75 (.020 – .
LTC2952 PACKAGE DESCRIPTION Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings. UF Package 20-Lead Plastic QFN (4mm × 4mm) (Reference LTC DWG # 05-08-1710 Rev A) 0.70 0.05 4.50 0.05 3.10 0.05 2.00 REF 2.45 0.05 2.45 0.05 PACKAGE OUTLINE 0.25 0.05 0.50 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 0.75 0.05 4.00 0.10 BOTTOM VIEW—EXPOSED PAD R = 0.05 TYP R = 0.115 TYP 19 20 0.40 0.
LTC2952 REVISION HISTORY REV DATE DESCRIPTION PAGE NUMBER A 02/10 Revised Configuration B of Figure 1 B 09/11 Added information to Typical Applications drawings Revised conditions for tONT, OFFT in Electrical Characteristics Revised EN, KILL, and WDE pin pin descriptions in Pin Functions Added information to Figures 1, 3, 4, 6, 7 and 8 Updated values in Applications Information 14 1, 24, 25, 26, 30 4 10, 11 14 to 18 20, 21 2952fb Information furnished by Linear Technology Corporation is believed
LTC2952 TYPICAL APPLICATION Wall Adapter and Battery Automatic Load Switchover with Reverse Battery Protection WALL ADAPTER 12V TO 25V 3.3V VIN Q1 Si6993DQ Q2 Si6993DQ VOUT LT1767-3.3 R6 10k SHDN** R3 1.3M 9V BATTERY 1k G1 R7 10k R1 511k R8 10k R4 100k VS R5 10k PFI G2 V1 R2 100k EN VM V2 RST LTC2952 M1 INT M2 G1STAT PB KILL μP PFO WDE ONT S1 GND OFFT CONT* 22nF COFFT* 68nF *OPTIONAL **SHDN INTERNALLY PULLED UP BY THE LT1767-3.
