TPS61071-Q1 90% Efficient Synchronous Boost Converter With 600-mA Switch
- SLVSAA5A May 2010 – December 2015 TPS61071-Q1
  
  UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.

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DATA SHEET

TPS61071-Q1 90% Efficient Synchronous Boost Converter With 600-mA Switch

1 Features

Qualified for Automotive Applications
AEC-Q100 Qualified With the Following Results:
- Device Temperature Grade 2: –40°C to 105°C Ambient Operating Temperature Range
- Device HBM Classification Level 1C
- Device CDM Classification Level C6
90% Efficient Synchronous Boost Converter
- 75-mA Output Current at 3.3 V From 0.9-V Input
- 150-mA Output Current at 3.3 V From 1.8-V Input
Device Quiescent Current: 19 µA (Typical)
Input Voltage Range: 0.9 V to 5.5 V
Adjustable Output Voltage Up to 5.5 V
Power-Save Mode Version Available for
Improved Efficiency at Low Output Power
Load Disconnect During Shutdown
Overtemperature Protection
Small 6-Pin Thin SOT Package

2 Applications

Automotive Power Supplies
Boost Power Supplies

3 Description

The TPS61071-Q1 device provides a power supply solution for products powered by lower-voltage DC rails or a one-cell, two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-ion or Li-polymer battery. Output currents can go as high as 75 mA, while using a single-cell alkaline, and discharge down to 0.9 V. The device can also generate 5 V at 200 mA from a 3.3-V rail or a Li-ion battery. The boost converter is based on a fixed frequency, pulse-width-modulation (PWM) controller using a synchronous rectifier to obtain maximum efficiency. The maximum peak current in the boost switch is limited typically to a value of 600 mA.

The TPS61071-Q1 output voltage is programmed by an external resistor divider. To minimize battery drain, disable the converter. During shutdown, the load disconnects from the battery. The device package is a 6-pin thin SOT package (DDC).

Device Information⁽¹⁾

PART NUMBER	PACKAGE	BODY SIZE (NOM)
TPS61071-Q1	SOT (6)	1.60 mm × 2.90 mm

For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application Circuit

4 Revision History

Changes from * Revision (May 2010) to A Revision

Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Supportsection, and Mechanical, Packaging, and Orderable Information sectionGo
Changed pinout illustration.Go
Deleted Dissipation Ratings sectionGo
Updated Soft Start and Short-Circuit Protection sectionGo
Updated Device EnablesectionGo
Changed Figure 20Go
Updated Inductor Selection sectionGo

5 Pin Configuration and Functions

DDC Package

6-Pin SOT

Top View

Pin Functions

PIN		I/O	DESCRIPTION
NO.	NAME	I/O	DESCRIPTION
1	SW	I	Boost and rectifying switch input
2	GND	—	Device (IC) ground connection for logic and power
3	EN	I	Enable input (1/VBAT enabled, 0/GND disabled)
4	FB	I	Voltage feedback for programming the output voltage
5	VOUT	O	Boost converter output
6	VBAT	I	Supply voltage

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)⁽¹⁾

	MIN	MAX	UNIT
Input voltage range on SW, VOUT, VBAT, EN, FB	–0.3	7	V
Operating virtual junction temperature, T_J	–40	150	°C
Storage temperature, T_stg	–65	150	°C

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

6.2 ESD Ratings

			VALUE	UNIT
V_(ESD)	Electrostatic discharge	Human-body model (HBM), per AEC Q100-002⁽¹⁾	±2000	V
V_(ESD)	Electrostatic discharge	Charged-device model (CDM), per AEC Q100-011	±1000	V

(1) AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

6.3 Recommended Operating Conditions

	MIN	MAX	UNIT
Supply voltage at VBAT, V_I	0.9	5.5	V
Operating free air temperature range, T_A	–40	105	°C
Operating virtual junction temperature range, T_J	–40	125	°C

6.4 Thermal Information

THERMAL METRIC⁽¹⁾		TPS61071-Q1	UNIT
		DDC (SOT)
		6 PINS
R_θJA	Junction-to-ambient thermal resistance	139.1	°C/W
R_θJC(top)	Junction-to-case (top) thermal resistance	34.8	°C/W
R_θJB	Junction-to-board thermal resistance	42.5	°C/W
ψ_JT	Junction-to-top characterization parameter	1.4	°C/W
ψ_JB	Junction-to-board characterization parameter	40.7	°C/W
R_θJC(bot)	Junction-to-case (bottom) thermal resistance	N/A	°C/W

(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

over recommended free-air temperature range and over recommended input voltage range (typical at an ambient temperature range of 25°C) (unless otherwise noted)

PARAMETER			TEST CONDITIONS	MIN	TYP	MAX	UNIT
DC-DC STAGE
V_I	Minimum input voltage range for start-up		R_L = 270 Ω		1.1	1.25	V
V_I	Input voltage range, after start-up		T_A = 25°C	0.9		5.5	V
V_O	Output voltage range			1.8		5.5	V
V_(FB)	Feedback voltage		T_A = 25°C	490	500	510	mV
f	Oscillator frequency			960	1200	1440	kHz
I_(SW)	Switch current limit		VOUT= 3.3 V	455	600	735	mA
	Start-up current limit				0.5 × I_SW		mA
	Boost switch-on resistance		VOUT= 3.3 V		480		mΩ
	Rectifying switch-on resistance		VOUT= 3.3 V		600		mΩ
	Total accuracy (including line and load regulation)					5%
	Line regulation				1%
	Load regulation				1%
	Quiescent current	VBAT	I_O= 0 mA, V_(EN)= VBAT = 1.2 V, VOUT = 3.3 V, T_A = 25°C		0.5	1	µA
		VOUT			190⁽¹⁾	300⁽¹⁾
		VOUT			20⁽²⁾
	Shutdown current		V_(EN) = 0 V, VBAT = 1.2 V, T_A = 25°C		0.05	0.5	µA
CONTROL STAGE
V_(UVLO)	Undervoltage lockout threshold		V_(BAT) voltage decreasing		0.8		V
V_IL	EN input low voltage					0.2 × VBAT	V
V_IH	EN input high voltage			0.8 × VBAT			V
	EN input current		Clamped on GND or VBAT		0.01	0.1	µA
	Overtemperature protection				140		°C
	Overtemperature hysteresis				20		°C

(1) Switching current

(2) Non-switching current

6.6 Typical Characteristics

Table 1. Table of Graphs

		FIGURE
Maximum output current	vs Input voltage	Figure 1
Efficiency	vs Output current	Figure 2
	vs Output current	Figure 3
	vs Output current	Figure 4
	vs Input voltage	Figure 5
	vs Input voltage	Figure 6
Output voltage	vs Output current	Figure 7
Output voltage	vs Output current	Figure 8
No load supply current into VOUT	vs Input voltage	Figure 9
Waveforms	Output voltage in continuous mode	Figure 10
	Output voltage in continuous mode	Figure 11
	Load transient response	Figure 12
	Load transient response	Figure 13
	Line transient response	Figure 14
	Line transient response	Figure 15
	Start-up after enable	Figure 16
	Start-up after enable	Figure 17

Figure 1. Maximum Output Current vs Input Voltage

Figure 3. Efficiency vs Output Current

Figure 5. Efficiency vs Input Voltage

Figure 7. Output Voltage vs Output Current

Figure 9. No Load Supply Current Into V_OUT vs Input Voltage

Figure 11. TPS61071 Output Voltage in Continuous Mode

Figure 13. TPS61071 Load Transient Response

Figure 15. TPS61071 Line Transient Response

Figure 17. TPS61071 Start-Up After Enable

Figure 2. Efficiency vs Output Current

Figure 4. Efficiency vs Output Current

Figure 6. Efficiency vs Input Voltage

Figure 8. Output Voltage vs Output Current

Figure 10. TPS61071 Output Voltage in Continuous Mode

Figure 12. TPS61071 Load Transient Response

Figure 14. TPS61071 Line Transient Response

Figure 16. TPS61071 Start-Up After Enable

7 Detailed Description

7.1 Overview

The TPS61071-Q1 provides a boost power supply solution for products powered by either DC supply rails or batteries such as one-cell, two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-ion or Li-polymer battery. Output currents can go as high as 75 mA, while using a single-cell alkaline, and discharge down to 0.9 V. The device can also generate 5 V at 200 mA from a 3.3-V rail or a Li-ion battery. The boost converter is based on a fixed frequency, pulse-width modulation (PWM) controller using a synchronous rectifier to obtain maximum efficiency. The TPS61071-Q1 does not have a POWER-SAVE mode. Even with low-load currents, the device is forced to operate at the fixed switching frequency. The maximum peak current in the boost switch is limited typically to a value of 600 mA. An external-resistor divider programs the output voltage. To minimize battery drain, disable the converter. During shutdown, the load disconnects from the battery.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Controller Circuit

The controller circuit of the device is based on a fixed-frequency multiple feed-forward controller topology. Input voltage, output voltage, and voltage drop on the NMOS switch are monitored and forwarded to the regulator. So, changes in the operating conditions of the converter directly affect the duty cycle and must not take the indirect and slow way through the control loop and the error amplifier. The control loop, determined by the error amplifier, only has to handle small signal errors. The input for it is the feedback voltage on the FB pin. It is compared with the internal reference voltage to generate an accurate and stable output voltage.

The peak current of the NMOS switch is also sensed to limit the maximum current flowing through the switch and the inductor. The typical peak-current limit is set to 600 mA. An internal temperature sensor prevents the device from getting overheated in case of excessive power dissipation.

7.3.1.1 Synchronous Rectifier

The device integrates an N-channel and a P-channel MOSFET transistor to realize a synchronous rectifier. Because the commonly used discrete Schottky rectifier is replaced with a low R_DS(on) PMOS switch, the power conversion efficiency reaches values above 90%. A special circuit is applied to disconnect the load from the input during shutdown of the converter. In conventional synchronous rectifier circuits, the backgate diode of the high-side PMOS is forward biased in shutdown and allows current flowing from the battery to the output. However, this device uses a special circuit, which takes the cathode of the backgate diode of the high-side PMOS and disconnects it from the source when the regulator is not enabled (EN = low).

The benefit of this feature for the system design engineer is that the battery is not depleted during shutdown of the converter. No additional components must be added to the design to make sure that the battery is disconnected from the output of the converter.

7.3.1.2 Undervoltage Lockout

An undervoltage lockout function prevents the device from operating if the supply voltage on VBAT is lower than approximately 0.8 V. When in operation and the battery is being discharged, the device automatically enters the shutdown mode if the voltage on VBAT drops below approximately 0.8 V. This undervoltage lockout function is implemented in order to prevent the malfunctioning of the converter.

7.3.1.3 Soft Start and Short-Circuit Protection

When the device enables, the internal start-up cycle starts with the first step, the precharge phase. During precharge, the rectifying switch is turned on until the output capacitor is charged to a value close to the input voltage. The rectifying switch is current limited during this phase. The current limit increases with the output voltage. This circuit also limits the output current under short-circuit conditions at the output. Figure 18 shows the typical precharge current vs output voltage for specific input voltages:

Figure 18. Precharge and Short Circuit Current

After charging the output capacitor to the input voltage, the device starts switching. If the input voltage is below 1.8 V, the device works with a fixed duty cycle of 70% until the output voltage reaches 1.8 V. After that the duty cycle is set depending on the input output voltage ratio. Until the output voltage reaches its nominal value, the boost switch current limit is set to 50% of its nominal value to avoid high peak currents at the battery during start-up. As soon as the output voltage is reached, the regulator takes control, and the switch current limit is set back to 100%.

7.4 Device Functional Modes

7.4.1 Device Enable

The device is put into operation when EN is set high and put into a SHUTDOWN mode when EN is set to GND. In SHUTDOWN mode, the regulator stops switching, all internal control circuitry switches off, and the device isolates the load from the input (see Synchronous Rectifier). This also means that the output voltage can drop below the input voltage during shutdown. During start-up of the converter, the duty cycle and the peak current are limited to avoid high-peak currents drawn from the battery.