APU3137 Advanced Power Electronics Corp., APU3137 Datasheet
APU3137
Specifications of APU3137
Related parts for APU3137
APU3137 Summary of contents
Page 1
... Data and specifications subject to change without notice. Technology Licensed from International Rectifier 8-PIN SYNCHRONOUS PWM CONTROLLER DESCRIPTION The APU3137 controller IC is designed to provide a low cost and high performance synchronous Buck regulator for on-board converter applications. The out- put voltage can be set as low as 0.8V and higher voltage can be obtained with an external voltage divider ...
Page 2
... APU3137 ABSOLUTE MAXIMUM RATINGS Vcc Supply Voltage .................................................. -0.5V - 25V Vc Supply Voltage .................................................... -0.5V - 25V Storage Temperature Range ...................................... -65°C To 150°C Operating Junction Temperature Range ..................... 0°C To 125°C CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. PACKAGE INFORMATION 8-PIN PLASTIC SOIC NB (M) ...
Page 3
... The converter can be shutdown by pulling this pin below 2.8V. TEST CONDITION SS=3V, Fb=1V SS=0V, Fb=1V Note 1 C =3000pF (10 =3000pF (90 Fb=0.7V, Freq=200KHz Fb=1.5V APU3137 MIN TYP MAX UNITS µA 0.1 µA 50 µmho 600 850 1100 KHz 180 240 V 1 ...
Page 4
... APU3137 BLOCK DIAGRAM Vcc 2 3V 4.25V 20uA Vc 3.5V SS/SD 8 64uA Max POR Error Amp 25K 0.8V 25K Fb 1 Comp 7 Figure 2 - Simplified block diagram of the APU3137. 3V Bias Generator 0.8V POR Oscillator Error Comp R Reset Dom FbLo Comp 0.4V POR HDrv Vcc 3 LDrv 2.8V 4 Gnd SS 4/17 ...
Page 5
... THEORY OF OPERATION Introduction The APU3137 is a fixed frequency, voltage mode syn- chronous controller and consists of a precision refer- ence voltage, an error amplifier, an internal oscillator, a PWM comparator, 1A peak gate driver, soft-start and shutdown circuits (see Block Diagram). The output voltage of the synchronous converter is set and controlled by the output of the error amplifier ...
Page 6
... The outputs are protected against the short-circuit. The APU3137 protects the circuit for shorted output by sens- ing the output voltage (through the external resistor di- vider). The APU3137 turns off both drivers, when the out- put voltage drops below 0.4V. The APU3137 also protects the output from over-voltaging when the control FET is shorted ...
Page 7
... APPLICATION INFORMATION Design Example: The following example is a typical application for APU3137, the schematic is Figure 13 on page 15. Supply V oltage 2.5V CC OUT I = 15A OUT ∆V = 75mV OUT (output voltage ripple ≅ OUT f = 200KHz S Output Voltage Programming Output voltage is programmed by reference voltage and external voltage divider ...
Page 8
... The capacitor value must be high enough to absorb the inductor's ripple current. The larger the value of capaci- tor, the lower will be the output ripple voltage. Power MOSFET Selection The APU3137 uses two N-Channel MOSFETs. The se- lections criteria to meet power transfer requirements is based on maximum drain-source voltage (V source drive voltage (V ...
Page 9
... P = 250mW SW(TOTAL) Feedback Compensation The APU3137 is a voltage mode controller; the control loop is a single voltage feedback path including error amplifier and error comparator. To achieve fast transient response and accurate output regulation, a compensa- tion circuit is necessary. The goal of the compensation ...
Page 10
... APU3137 The APU3137’s error amplifier is a differential-input transconductance amplifier. The output is available for DC gain control or AC phase compensation. The E/A can be compensated with or without the use of local feedback. When operated without local feedback, the transconductance properties of the E/A become evi- dent and can be used to cancel one of the output filter poles ...
Page 11
... Compensator Type Type II (PI) Type III (PID) Method A Type III (PID) Method B Table - The compensation type and location of zero Detail information is dicussed in application Note AN- 1043 which can be downloaded from the IR Web-Site. APU3137 1 × ≅ ×C 2π×R ( ×C ) ...
Page 12
... APU3137 Layout Consideration The layout is very important when designing high fre- quency switching converters. Layout will affect noise pickup and can cause a good design to perform with less than expected results. Start to place the power components. Make all the con- nections in the top layer with wide, copper filled areas. ...
Page 13
... TYPICAL APPLICATION Single Supply 5V Input C3 0.1uF Vcc Vc U1 SS/SD C8 APU3137 0.1uF Comp C9 3.3nF C6 Gnd 68pF R4 18K Figure 11 - Typical application of APU3137 in an on-board DC-DC converter D2 D1 BAT54 BAT54S C4 1uF C5 0.1uF Q1 HDrv IRF7457 D3 BAT54 Q2 LDrv IRF7457 R6 Fb 3.16K 1K, 1% using a single 5V supply. APU3137 5V L1 ...
Page 14
... APU3038 C12 0.15uF Rt Comp C14 6800pF Gnd C16 47pF R6 12K Figure 12 - Typical application of APU3137 for DDR memory when the termination voltage, generated by APU3038, tracks the core voltage. 12V C2 1uF C5 4x 150uF 6TPB150M Vc Q1 HDrv IRF3711S D1 1N4148 Q2 LDrv IRF3711S R1 ...
Page 15
... C1 150uF 150uF Gnd 12V Vcc C3 1uF SS/SD U1 APU3137 C8 0.1uF Comp C15 Gnd 3300pF C13 R9 47pF 30K Figure 13 - Demo-board application of APU3137. Application Parts List Ref Desig Description Q1, Q2 MOSFET U1 Controller D3 Diode L1 Inductor L2 Inductor C1,C18,C19,C20,C23 Capacitor, Poscap C10,C11,C21 Capacitor, Poscap C8 Capacitor, Ceramic C3,C4,C12,C6 Capacitor, Ceramic ...
Page 16
... APU3137 TYPICAL OPERATING CHARACTERISTICS Figure 14 - Transient load response at I Ch1: V OUT Ch4: I (5A/div) OUT Figure 15 - Normal condition at N/L. Ch1: Output Voltage Ripple (20mV/div) Ch2: HDrv Ch3: LDrv Ch4: Inductor Current (2A/div) =0A - 8A. Figure 16 - Transient load response at I OUT Ch1: V OUT Ch4: I (5A/div) OUT Figure 17 - Normal condition at 15A ...
Page 17
... Ch1: V OUT Ch2: HDrv Ch3: LDrv Ch4: I (10A/div) OUT 120 100 Output Current (A) Figure 20 - Application circuit efficiency at ambient temperature 2.5V APU3137 Figure 19 - Start-Up. Ch2: V (Soft-Start Voltage) SS Ch3: V OUT Ch4: I (5A/div) OUT 17/17 ...