PS7516 升压模块规格说明书
PS7516
The PS7516 is a high efficiency, fixed frequency 1MHz, current mode PWM boost DC/DC converter The converter is based on a fixed frequency, current When converter operation into discontinuous mode, The PS7516 is ava ●Fixed 1MHz Switching Frequency
● Low-Power Mode for Light Load Conditions ● ±2.0% Voltage Reference Accuracy
● PMOS Current Limit for Short Circuit Protection ● Low Quiescent Current
● Output Ripple under 200mV. (Scope Full Bandwidth)
● Fast Transient Response ● Built-In Soft Start Function
● Over-Temperature Protection with Auto Recovery ● Output Overvoltage Protection ●
Space-Saving SOT-23-6 Package
Applications
● Portable Power Bank ● Wireless Equipment ● Handheld Instrument ●
GPS Receiver
IN
.
Description
which could operate battery such as input voltage down to 2.5V. The converter output voltage can be adjusted to a maximum of 5.25V by an external resistor divider. Besides the converter includes a 0.08Ω N -channel MOSFET switch and 0.12Ω P-channel synchronous rectifier. So no external Schottky diode is required and could get better efficiency near 93%.
mode, pulse-width-modulation PWM controller that goes automatically into PSM mode at light load. the internal anti-ringing switch will reduce interference and radiated electromagnetic energy. ilable in a space-saving SOT-23-6 package for portable application.
Features
High Efficiency up to 96% (When Vin = 4.2V) ● Low R DS (ON) Integrated Power MOSFET ● NMOS 80mΩ / PMOS120mΩ
● Wide Input Voltage Range: 2.5V to 5.5V ● Pin Assignments
SOT -23-6
2
1
3
645LX IN GND OUT EN
FB
Fig ure 1. Pin Assignment of PS7516
Functional Pin Description
Pin Name Pin No. Pin Function
EN 4 Logic Controlled Shutdown Input. GND 2 Ground Pin.
LX 1 Power Switching Connection. Connect LX to the inductor and output rectifier. IN
6
Power Supply Input Pin.
OUT 5 Output of the Synchronous Rectifier. FB 3 Voltage Feedback Input Pin. High Efficiency up to 96%
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Control
Control Isense/Current Limit
Body-Diode Reference
Error Comparator
PFM
.
PS7516
Block Diagram
On/Off OUT
FB
PWM Logic
Slope Comp.
COMP
Switch
Bandgap Amp
Anti-Reverse NMOS
GND
ANTI-RING
PMOS
EN
LX
VIN
Control UVLO
VIN
OSC OVP OTP
Figure 3. Block Diagram of PS7516
VOUT
10C4, C6C , C50.1Absolute Maximum Ratings (Note 1)
● Supply Voltage V IN --------------------------------------------------------------------------------------------- -0.3V to +6.5V ● LX Voltage V LX -------------------------------------------------------------------------------------------------- -0.3V to +6.5V ● All Other Pins Voltage ----------------------------------------------------------------------------------------- -0.3V to +6.5V ● Maximum Junction Temperature (T J ) --------------------------------------------------------------------- +150°C ● Storage Temperature (T S ) ----------------------------------------------------------------------------------- -65°C to +150°C ● Lead Temperature (Soldering, 10sec.) ------------------------------------------------------------------- +260°C ● Package Thermal Resistance (θJA )
SOT-23-6 ---------------------------------------------------------------------------------------------- +250°C/W
● Package Thermal Resistance (θJC )
SOT-23-6 ---------------------------------------------------------------------------------------------- +130°C/W
Note 1：Stresses beyond this listed under “Absolute Maximum Ratings" may cause permanent damage to the device.
Recommended Operating Conditions
● Supply Voltage V IN --------------------------------------------------------------------------------------------- +2.5V to +5.5V ● Output Voltage Range ---------------------------------------------------------------------------------------- up to +5.25V ● Operation Temperature Range ------------------------------------------------------------------------------ -40°C to +85°C
Typical Application Circuit
PS7516VIN
EN GND
LX
FB
OUT
L1
10μH
C1μF
C60.1μF
R1525K
R2100K
6
2
41
5
3
VIN 5V/1A
2.5V to 5.5V
OFF
ON
C522μF
C2μF
Figure 2. Typical Application Circuit
Under Supply Current (Switching) High-Side MOSFET Leakage 450 Thermal Shutdown Threshold Electrical Characteristics
(V IN =3.3V, T A =25°C , unless otherwise specified.)
Parameter
Symbol Conditions
Min Typ Max Unit V IN Input Supply Voltage V IN
2.5 5.5 V Input UVLO Threshold
V IN Rising 1.85 V Voltage Lockout Threshold Hysteresis
V IN Falling
0.2 V Supply Current 45 μA Feedback Voltage
V FB 2.5V ≦V IN ≦5.5V
0.784 0.8 0.816 V High-Side PMOSFET R DS (ON) 120 mΩ Low-Side NMOSFET R DS (ON)
80 mΩ Current
I LX(leak) V LX =5.5V, V OUT =0V 10 μA Low-Side MOSFET Leakage Current V LX =5.5V 10 μA Oscillation Frequency F OSC
1000 KHz Switch Current Limit V IN =3.3V
2.5 A Short Circuit Trip Point Monitored FB voltage 0.3 V Short Circuit Current Limit V IN =
3.3V 50 mA Maximum Duty Cycle D MAX V IN =3.3V
85 90 % Line Regulation V IN =2.5V to 5.5V, I OUT =100mA 1 % Load Regulation
I OUT =0A to 1A 0.5 % OVP Threshold Voltage on OUT Pin 6 V OVP Threshold Hysteresis 500 mV Internal Soft-Start Time 1 3 ms EN Input Low Voltage V EN (L)
0.4 V EN Input High Voltage V EN (H)
1.4 V EN Input Current
I EN V IN =3.3V
2 μA (Note 2)
T SD 150 °C Thermal Shutdown Hysteresis
30
°C
Note 2：Not production tested.
50
Controller Circuit
The The PS7516 is designed for high efficiency over Device Enable
The The accuracy of the output voltage is determined by The PS7516 boost converter family is intended for
Application Information
The device is based on a current-mode control topology and uses a constant frequency pulse-width modulator to regulate the output voltage. The controller limits the current through the power switch on a pulse by pulse basis. The current sensing circuit is integrated in the device; therefore, no additional components are required. Due to the nature of the boost converter topology used here, the peak switch current is the same as the peak inductor current, which will be limited by the integrated current limiting circuits under normal operating conditions. Synchronous Rectifier
device integrates an N-channel and a P- channel MOSFET transistor to realize a synchronous rectifier. There is no additional Schottky diode required. Because the device uses a integrated low R DS(ON) PMOS switch for rectification, the power conversion efficiency reaches 93%.
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. This device, however, uses a special circuit to disconnect the backgate diode of the high-side PMOS and so, disconnects the output circuitry from the source when the regulator is not enabled (EN=low). PSM Mode
wide output current range. Even at light load, the efficiency stays high because the switching losses of the converter are minimized by effectively reducing the switching frequency. The controller will enter a power saving mode if certain conditions are met. In this mode, the controller only switches on the transistor if the output voltage trips below a set threshold voltage. It ramps up the output voltage with one or several pulses, and goes again into PSM mode once the output voltage exceeds a set threshold voltage.
The device will be shut down when EN is set to GND. In this mode, the regulator stops switching, all internal control circuitry including the low-battery comparator will be switched off, and the load will be disconnected from the input (as described in above synchronous rectifier section). This also means that the output voltage may drop below the input voltage during shutdown.
The device is put into operation when EN is set high. During start-up of the converter, the duty cycle is limited in order to avoid high peak currents drawn from the battery. The limit is set internally by the current limit circuit. Anti-Ringing Switch
device integrates a circuit which removes the ringing that typically appears on the SW node when the converter enters the discontinuous current mode. In this case, the current through the inductor ramps to zero and the integrated PMOS switch turns off to prevent a reverse current from the output capacitors back to the battery. Due to remaining energy that is stored in parasitic components of the semiconductors and the inductor, a ringing on the SW pin is induced. The integrated anti-ringing switch clamps this voltage internally to V IN ; therefore, dampens this ringing. Adjustable Output Voltage
the accuracy of the internal voltage reference, the controller topology, and the accuracy of the external resistor. The reference voltage has an accuracy of ±2%. The controller switches between fixed frequency and PSM mode, depending on load current. The tolerance of the resistors in the feedback divider determines the total system accuracy.
Design Procedure
systems that are powered by a single-cell Ion battery with a typical terminal voltage between 3V to 4.2V.
(1) Programming the Output Voltage
A Parameter Parameter f is the switching frequency and The The total A Application Information (Continued)
The output voltage of the PS7516 can be adjusted with an external resistor divider. The typical value of the voltage on the FB pin is 800mV in fixed frequency operation. The maximum allowed value for the output voltage is 5.5V. The current through the resistive divider should be about 100 times greater than the current into the FB pin. The typical current into the FB pin is 0.01μA, and the voltage across R2 is typically 800mV. Based on those two values, the recommended value for R2 is in the range of 800k? in order to set the divider current at 1μA. From that, the value of resistor R1, depending on the needed output voltage (V O ), can be calculated using Equation 1.
R1 R2
O T F
-1 800kΩ
O T 800m
-1 (1)
(2) Inductor Selection
boost converter normally requires two main passive components for storing energy during the conversion. A boost inductor is required and a storage capacitor at the output. To select the boost inductor, it is recommended to keep the possible peak inductor current below the current limit threshold of the power switch in the chosen configuration.
The second parameter for choosing the inductor is the desired current ripple in the inductor. Normally, it is advisable to work with a ripple of less than 20% of the average inductor current. A smaller ripple reduces the magnetic hysteresis losses in the inductor, as well as output voltage ripple and EMI. But in the same way, regulation time at load changes rises. In addition, a larger inductor increases the total system cost. With those parameters, it is possible to calculate the value for the inductor by using Equation 2.
N O T - N O T
(2)
is the switching requency and Δ L is the ripple current in the inductor, i.e, 20% x I L . With this calculated value and currents, it is possible to choose a suitable inductor. Care must be taken that load transients and losses in the circuit can lead to higher currents. Also, the losses in the inductor caused by magnetic hysteresis losses and copper losses are a major parameter for total circuit efficiency.
(3) Capacitor Selection
The major parameter necessary to define the output capacitor is the maximum allowed output voltage ripple of the converter. This ripple is determined by two parameters of the capacitor, the capacitance and the ESR. It is possible to calculate the minimum capacitance needed for the defined ripple, supposing that the ESR is zero, by using Equation 3.
M N
O T O T - N O T
(3)
△V is the maximum allowed ripple.
total ripple is larger due to the ESR of the output capacitor. This additional component of the ripple can be calculated using Equation 4.
ESR O T R ESR (4)
ripple is the sum of the ripple caused by the capacitance and the ripple caused by the ESR of the capacitor. It is possible to improve the design by enlarging the capacitor or using smaller capacitors in parallel to reduce the ESR or by using better capacitors with lower ESR, like ceramics. Tradeoffs must be made between performance and costs of the converter circuit.
10μF input capacitor is recommended to improve transient behavior of the regulator. A ceramic or tantalum capacitor with a 100nF in parallel placed close to the IC is recommended.
PS7516
As for all switching power supplies, the layout is an 1
6
.
Application Information (Continued)
Layout Considerations
important step in the design, especially at high peak currents and high switching frequencies. If the layout is not carefully done, the regulator could show stability problems as well as EMI problems. Therefore, use wide and short traces for the main current path as indicated in bold in Figure 4. The input capacitor, output capacitor and the inductor should be placed as close to the IC as possible. Use a common ground node as shown in Figure 4 to minimize the effects of ground noise. The feedback divider should be placed as close to the IC as possible.
GND
VOUT
VIN
LX
GND 3
L1
C1
R2
R1
C2
C4
C3C6
C5
2
4
5Figure 4. Layout Diagram
PS7516
SYMBOLS DIMENSION IN MILLIMETER
Outline Information
SOT-23-6 Package (Unit: mm)
UNIT
MIN MAX
A 0.90 1.45 A1 0.00 0.15 A2 0.90 1.30
B 0.30 0.50 D 2.80 3.00 E 2.60 3.00 E1 1.50 1.70 e 0.90 1.00 e1 1.80 2.00 L
0.30
0.60
Note ：Followed From JEDEC MO-178-C.
Carrier Dimensions
PS7516