LLC Current-Resonant Off-Line Switching Control IC SSC9522S Data Sheet Description Package The SSC9522S is a controller IC (SMZ* method) for half-bridge resonant type power supply, incorporating a floating drive circuit for the high-side power MOSFET drive. The product achieves high efficiency, low noise and high cost-performance power supply systems with few external components. *SMZ; Soft-switched Multi-resonant Zero Current switch (All switching periods work with soft switching operation.) SOP18 Features ● Absolute maximum rating of VCC pin is 35 V ● Minimum oscillation frequency is 28.3 kHz (typ.) ● Maximum oscillation frequency is 300 kHz (typ.) Not to Scale Electrical Characteristics ● Built-in floating drive circuit for high-side power MOSFET ● Soft Start Function ● Capacitive Mode Operation Detection Function (Pulse-by-pulse) ● Automatic Dead Time Adjustment Function ● Brown-in and Brown-out Function ● Protections High-side Driver UVLO Protection External Latched Shutdown Function Overcurrent Protection (OCP): Three steps protection corresponding to overcurrent levels Overload Protection (OLP): Latched shutdown Overvoltage Protection (OVP): Latched shutdown Thermal Shutdown (TSD): Latched shutdown Application ● ● ● ● Digital appliance Office automation equipment Industrial equipment Communication equipment, etc Typical Application R1 BR1 VAC C1 R2 R3 D1 R8 RB(H) DS(H) Q(H) 14 VB VGH REG VS SSC9522S RB(L) DS(L) U1 VGL VCC PC1 Q(L) C51 Cv RA(L) RGS(L) GND 4 RV C2 FB CSS 3 External power supply D51 11 2 C9 RGS(H) 15 VSEN 1 D2 T1 RA(H) 8 R4 C10 16 5 R5 R6 C4 PC1 C5 OC 6 COM RC RC D52 9 10 CRV 7 C11 R7 C3 C6 C7 Ci C8 SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 ROCP C12 1 SSC9522S Series CONTENTS Description ------------------------------------------------------------------------------------------------------ 1 CONTENTS ---------------------------------------------------------------------------------------------------- 2 1. Absolute Maximum Ratings----------------------------------------------------------------------------- 3 2. Electrical Characteristics -------------------------------------------------------------------------------- 4 3. Block Diagram --------------------------------------------------------------------------------------------- 6 4. Pin Configuration Definitions --------------------------------------------------------------------------- 6 5. Typical Application --------------------------------------------------------------------------------------- 7 6. External Dimensions -------------------------------------------------------------------------------------- 8 7. Marking Diagram ----------------------------------------------------------------------------------------- 8 8. Operational Description --------------------------------------------------------------------------------- 9 8.1 Resonant Circuit Operation ----------------------------------------------------------------------- 9 8.2 Startup Operation --------------------------------------------------------------------------------- 12 8.3 Soft Start Function -------------------------------------------------------------------------------- 13 8.4 High-side Driver ----------------------------------------------------------------------------------- 13 8.5 Constant Output Voltage Control-------------------------------------------------------------- 13 8.6 Automatic Dead Time Adjustment Function ------------------------------------------------ 14 8.7 Capacitive Mode Operation Detection Function -------------------------------------------- 15 8.8 Brown-in and Brown-out Function ------------------------------------------------------------ 16 8.9 External Latched Shutdown Function -------------------------------------------------------- 17 8.10 Overcurrent Protection (OCP) ----------------------------------------------------------------- 17 8.11 Overload Protection (OLP) ---------------------------------------------------------------------- 18 8.12 Overvoltage Protection (OVP) ------------------------------------------------------------------ 19 8.13 Thermal Shutdown (TSD) ----------------------------------------------------------------------- 19 9. Design Notes ---------------------------------------------------------------------------------------------- 19 9.1 External Components ---------------------------------------------------------------------------- 19 9.2 PCB Trace Layout and Component Placement --------------------------------------------- 20 OPERATING PRECAUTIONS -------------------------------------------------------------------------- 21 IMPORTANT NOTES ------------------------------------------------------------------------------------- 22 SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 2 SSC9522S Series 1. Absolute Maximum Ratings ● The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC. ● Unless otherwise specified TA = 25 °C Characteristic Symbol Conditions Pin Rating Units VSEN Pin Voltage VSEN 1−4 − 0.3 to VREG V VCC Pin Voltage VCC 2−4 − 0.3 to 35 V FB Pin Voltage VFB 3−4 − 0.3 to 10 V CSS Pin Voltage VCSS 5−4 − 0.3 to 12 V OC Pin Voltage VOC 6−4 − 6 to 6 V RC Pin Voltage VRC 7−4 − 6 to 6 V REG Pin Source Current IREG 8−4 − 20.0 mA RV Pin Current IRV DC 9−4 − 2 to 2 mA Pulse 40 ns 9−4 − 100 to 100 mA VGL Pin Voltage Voltage between VB Pin and VS Pin VS Pin Voltage VGL 11 − 4 − 0.3 to VREG + 0.3 V VB−VS 14 − 15 − 0.3 to 15.0 V VS 15 − 4 − 1 to 600 V VGH Pin Voltage VGH 16 − 4 VS − 0.3 to VB + 0.3 V Operating Ambient Temperature TOP − − 20 to 85 °C Storage Temperature Tstg − − 40 to 125 °C Tj Junction Temperature − 150 *The pin 14, pin 15 and pin 16, are guaranteed 1000 V of ESD withstand voltage (Human body model). Other pins are guaranteed 2000V of ESD withstand voltage. SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 °C 3 SSC9522S Series 2. Electrical Characteristics ● The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC ● Unless otherwise specified, TA = 25 °C, VCC = 15 V Characteristic Symbol Conditions Pin Min. Typ. Max. Unit VCC(ON) 2−4 10.2 11.8 13.0 V VCC(OFF) 2−4 8.8 9.8 10.9 V Circuit Current in Operation ICC(ON) 2−4 − − 20.0 mA Circuit Current in Non-operation Circuit Current in Latched Shutdown Operation Soft Start ICC(OFF) VCC = 9 V 2−4 − − 1.2 mA ICC(L) VCC = 11 V 2−4 − − 1.2 mA CSS Pin Charge Current ICSS(C) 5−4 − 0.21 − 0.18 − 0.15 mA CSS Pin Reset Current ICSS(R) VCC = 9 V 5−4 1.0 1.8 2.4 mA VCSS(2) VSEN = 3 V VOC = 0 V 5−4 0.50 0.59 0.68 V Minimum Oscillation Frequency f(MIN) VCC = 9 V 26.2 28.3 31.2 kHz Maximum Oscillation Frequency f(MAX) IFB = − 2 mA 265 300 335 kHz Maximum Dead Time td(MAX) VSEN = 3 V 1.90 2.45 3.00 μs Minimum Dead Time td(MIN) IFB = − 2 mA 0.25 0.50 0.75 μs 5−4 70 105 130 Hz ICONT(1) 3−4 − 2.9 − 2.5 − 2.1 mA ICONT(2) 3−4 − 3.7 − 3.1 − 2.5 mA 8−4 9.9 10.5 11.1 V VBUV(ON) 14 − 15 6.3 7.3 8.3 V VBUV(OFF) 14 − 15 5.5 6.4 7.2 V 11 − 10 16 − 15 − – 515 − mA Startup Circuit and Circuit Current Operation Start Voltage Operation Stop Voltage (1) ON / OFF CSS Pin Threshold Voltage (2) Oscillator 11 − 10 16 − 15 11 − 10 16 − 15 11 − 10 16 − 15 11 − 10 16 − 15 Standby Operation Burst Oscillation frequency Feedback control FB Pin Source Current at Burst Mode Start FB Pin Source Current at Oscillation stop Supply of Driver Circuit REF Pin Output Voltage High-side Drive Circuit High-side Driver Operation Start Voltage High-side Driver Operation Stop Voltage Drive Circuit Source Current 1 of VGL Pin and VGH Pin (1) fCSS VREG IGLSOURCE1 IGHSOURCE1 IFB = – 3.5 mA IFB = – 2 mA VREG = 10.5V VB = 10.5 V VGL = 0 V VGH = 0 V VCC(OFF) < VCC(ON) SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 4 SSC9522S Series Characteristic Pin Min. Typ. Max. Unit 11 − 10 16 − 15 − 685 − mA 11 − 10 16 − 15 – 120 – 85 – 50 mA 11 − 10 16 − 15 70 113 160 mA VSEN Pin Threshold Voltage (ON) VSEN(ON) VSEN Pin Threshold Voltage VSEN(OFF) (OFF) Detection of Voltage Resonant Voltage Resonant Detection VRV(1) Voltage (1) Voltage Resonant Detection VRV(2) Voltage (2) Detection of Current Resonant and OCP 1−4 1.32 1.42 1.52 V 1−4 1.08 1.16 1.24 V 9−4 3.8 4.9 5.4 V 9−4 1.20 1.77 2.30 V Capacitive Mode Operation Detection Voltage VRC 7−4 0.055 0.155 0.255 V – 0.255 – 0.155 – 0.055 V RC Pin Threshold Voltage (High Speed) VRC(S) 7−4 2.15 2.35 2.55 V – 2.55 – 2.35 – 2.15 V OC Pin Threshold Voltage (Low) VOC(L) VCSS = 3 V 6−4 1.42 1.52 1.62 V OC Pin Threshold Voltage (High) OC Pin Threshold Voltage (High Speed) VOC(H) VCSS = 3 V 6−4 1.69 1.83 1.97 V VOC(S) VCSS = 5 V 6−4 2.15 2.35 2.55 V CSS Pin Sink Current (Low) ICSS(L) 5−4 1.0 1.8 2.4 mA CSS Pin Sink Current (High) ICSS(H) VCSS = 3 V VOC = 1.65 V VCSS = 3 V VOC = 2 V 5−4 12.0 20.0 28.0 mA CSS Pin Sink Current (High Speed) ICSS(S) VRC = 2.8 V 5−4 11.0 18.3 25.0 mA VFB = 5 V Sink Current 1 of VGL Pin and VGH Pin Source Current 2 of VGL Pin and VGH Pin Sink Current 2 of VGL Pin and VGH Pin Symbol IGLSINK1 IGHSINK1 IGLSOURCE2 IGHSOURCE2 IGLSINK2 IGHSINK2 Conditions VREG = 10.5V VB = 10.5 V VGL = 10.5 V VGH = 10.5 V VREG = 12 V VB = 12 V VGL = 10.5 V VGH = 10.5 V VREG = 12 V VB = 12 V VGL = 1.5 V VGH = 1.5 V Brown-in / Brown-out Function OLP Latch and External Latch FB Pin Source Current IFB 3−4 − 30.5 − 25.5 − 20.5 μA FB Pin Threshold Voltage VFB 3−4 6.55 7.05 7.55 V VCSS(1) 5−4 7.0 7.8 8.6 V VCC(LA_OFF) 2−4 6.7 8.2 9.5 V CSS Pin Threshold Voltage (1) Latched Circuit Release VCC Voltage (2) OVP and TSD VCC Pin OVP Threshold Voltage VCC(OVP) 2−4 28.0 31.0 34.0 V Thermal Shutdown Temperature Tj (TSD) − 150 − − °C θj−A − − − 95 °C/W Thermal Resistance Thermal Resistance Junction to Ambient (2) VSEN = 3 V VCC(LA_OFF) < VCC(OFF) SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 5 SSC9522S Series 3. Block Diagram 14 VB VCC 2 UVLO Start/Stop Reg/Bias OVP/TSD/Latch 16 VGH Level shift 15 VS High-side driver GND 4 VCC VSEN 1 Input sense 8 REG Main logic 11 VGL OLP 10 COM FB 3 CSS 5 4. Frequency control FB control Dead time Freq. Max. Soft-start/OC Standby control RC detector 7 RC RV detector 9 RV OC detector 6 OC Pin Configuration Definitions 1 VSEN (NC) 18 Number 1 Name VSEN 2 VCC (NC) 17 2 VCC 3 FB VGH 16 3 FB 4 GND VS 15 5 CSS VB 14 6 OC (NC) 13 7 RC (NC) 12 8 REG VGL 11 9 RV COM 10 4 5 6 7 8 9 10 11 12, 13 14 15 16 17, 18 GND CSS OC RC REG RV COM VGL (NC) VB VS VGH (NC) Function AC input voltage detection signal input Power supply voltage input for the IC, and Overvoltage Protection (OVP) signal input Feedback signal input for constant voltage control signal, and Overload Protection (OLP) signal input Ground for control part Soft start capacitor connection Overcurrent Protection (OCP) signal input Resonant current detection signal input Power supply output for high-side gate drive Resonant voltage detection signal input Ground for power part Low-side gate drive output − Power supply input for high-side gate drive Floating ground for high-side driver High-side gate drive output − SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 6 VAC BR1 C1 R4 R3 C2 C3 4 External power supply C9 2 1 8 D1 C4 R5 3 FB GND VCC VSEN REG 14 VB 6 OC C6 C7 5 CSS U1 SSC9522S PC1 C5 R6 R8 R7 COM C8 7 RC RV VGL VS VGH 10 9 11 15 16 RGS(H) RGS(L) CRV RA(L) RB(L) DS(L) RA(H) RB(H) DS(H) Q(L) Q(H) Ci Cv D2 ROCP C11 C10 C12 T1 D52 D51 C51 PC1 5. R2 R1 SSC9522S Series Typical Application SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 7 SSC9522S Series 6. External Dimensions ● SOP18 NOTES: ● Dimension is in millimeters ● Pb-free. Device composition compliant with the RoHS directive 7. Marking Diagram 18 SSC9522S Part Number SKYMD XXXX 1 Lot Number Y is the last digit of the year (0 to 9) M is the month (1 to 9,O,N or D) D is a period of days 1 : 1st to 10th 2 : 11th to 20th 3 : 21st to 31st Sanken Control Number SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 8 SSC9522S Series 8. Operational Description All of the parameter values used in these descriptions are typical values, unless they are specified as minimum or maximum. With regard to current direction, "+" indicates sink current (toward the IC) and "–" indicates source current (from the IC). Q(H) and Q(L) indicate a high-side power MOSFET and a low-side power MOSFET respectively. Ci, and CV indicate a current resonant capacitor and a voltage resonant capacitor respectively. 8.1 Resonant Circuit Operation Figure 8-1 shows a basic RLC series resonant circuit. R L C Figure 8-1 RLC series resonant circuit The impedance of the circuit, Ż, is as the following Equation. (1) where, ω is angular frequency and ω = 2πf. The frequency in which Ż becomes minimum value is the resonant frequency, f0. The higher frequency area than f0 is the inductance area, and the lower frequency area than f0 is the capacitance area. From Equation (3), f0 is as follows; (4) Figure 8-3 shows the circuit of a current resonant power supply. The basic configuration of the current resonant power supply is a half-bridge converter. The switching device Q(H) and Q(L) are connected in series with VIN. The series resonant circuit and the voltage resonant capacitor CV are connected in parallel with Q(L). The series resonant circuit is comprised of a resonant inductor LR, a primary winding P of a transformer T1 and a current resonant capacitor Ci. In the resonant transformer T1, the coupling between primary winding and secondary winding is designed to be poor so that the leakage inductance increases. By using it as LR, the series resonant circuit can be down sized. The dotted mark in T1 shows the winding polarity, the secondary windings S1 and S2 are connected so that the polarities are set to the same position shown in Figure 8-3, and the winding numbers of each other are equal. From Equation (1), the impedance of current resonant power supply is calculated by Equation (5). From Equation (4), the resonant frequency, f0, is calculated by Equation (6). (5) (2) When the frequency, f, changes, the impedance of resonant circuit will change as shown in Figure 8-2 where, R: the equivalent resistance of load LR: the inductance of the resonant inductor LP: the inductance of the primary winding P Ci: the capacitance of current resonant capacitor Inductance area Impedance Capacitance area (6) ID(H) R Q(H) f0 Frequency Series resonant circuit VDS(H) VGH LR T1 IS1 VIN Figure 8-2 Impedance of resonant circuit ID(L) Q(L) In Equation (2), Ż becomes minimum value (= R) at 2πfL = 1/2πfC, and then ω is calculated by Equation (3) . Cv P S1 LP VGL VDS(L) VCi ICi (3) VOUT (+) S2 Ci (−) IS2 Figure 8-3 Current resonant power supply circuit SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 9 SSC9522S Series In the current resonant power supply, Q(H) and Q(L) are alternatively turned on and off. The on time and off time of them are equal. There is a dead time between Q(H) on period and Q(L) on period. During the dead time, both Q(H) and Q(L) are in off status. The current resonant power supply is controlled by the frequency control. When the output voltage decreases, the IC makes the switching frequency low so that the output power is increased and the output voltage is kept constant. This control must operate in the inductance area (fSW > f0). Since the winding current is delayed from the winding voltage in the inductance area, the turn-on operation is ZCS (Zero Current Switching) and the turn-off operation is ZVS (Zero Voltage Switching). Thus, the switching loss of Q(H) and Q(L) is nearly zero, In the capacitance area (fSW < f0), the current resonant power supply operates as follows. When the output voltage decreases, the switching frequency is decreased, and then the output power is more decreased. Thus, the output voltage cannot be kept constant. Since the winding current goes ahead of the winding voltage in the capacitance area, the operation with hard switching occurs in Q(H) and Q(L). Thus, the power loss increases. This operation in the capacitance area is called the capacitive mode operation. The current resonant power supply must be operated without the capacitive mode operation (refer to Section 8.7 about details of it). Figure 8-4 shows the basic operation waveform of current resonant power supply (see Figure 8-3 about the symbol in Figure 8-4). The current resonant waveforms in normal operation are divided a period A to a period F. The current resonant power supply operates in the each period as follows. In following description, ID(H) is the current of Q(H), ID(L) is the current of Q(L), VF(H) is the forwerd voltage of Q(H), VF(L) is the forwerd voltage of Q(L), IL is the current of LR, VIN is an input voltage, VCi is Ci voltage, and VCV is CV voltage. 1) Period A When Q(H) is ON, energy is stored into the series resonant circuit by ID(H) flowing through the resonant circuit and the transformer as shown in Figure 8-5. At the same time, the energy is transferred to the secondary circuit. When the primary winding voltage can not keep the secondary rectifier ON, the energy to the secondary circuit is stopped. 2) Period B After the secondary side current becomes zero, the resonant current flows to the primary side only as shown in Figure 8-6 and Ci is charged by it. VGH VGL VDS(H) VIN+VF(H) ID(H) VDS(L) ID(L) ICi VCi VIN IS1 IS2 A B D E C F Figure 8-4 The basic operation waveforms of current resonant power supply Q(H) ID(H) ON LR LP VIN S1 Q(L) IS1 Cv VCV OFF S2 Ci VCi Figure 8-5 Operation in period A Q(H) ID(H) ON LR LP VIN S1 Q(L) Cv OFF S2 Ci Figure 8-6 Operation in period B SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 10 SSC9522S Series 3) Period C Pireod C is the dead-time. Both Q(H) and Q(L) are in off-state. When Q(H) turns off, IL is flowed by the energy stored in the series resonant circuit as shown in Figure 8-7, and CV is discharged. When VCV decreases to VF(L), −ID(L) flows through the body diode of Q(L) and VCV is clamped to VF(L). After that, Q(L) turns on. Since VDS(L) is nearly zero at the point, Q(L) operates in ZVS and ZCS. Thus, switching loss is nearly zero. Q(H) LR OFF LP VIN IL Q(L) Cv VCV OFF -ID(L) Ci Figure 8-7 Operation in period C 4) Period D When Q(L) turns on, ID(L) flows as shown in Figure 8-8 and the primary winding voltage of the transformer adds VCi. At the same time, energy is transferred to the secondary circuit. When the primary winding voltage can not keep the secondary rectifier ON, the energy to the secondary circuit is stopped. Q(H) LR OFF LP VIN ID(L) Q(L) S1 Cv ON 5) Period E After the secondary side current becomes zero, the resonant current flows to the primary side only as shown in Figure 8-9 and Ci is charged by it. S2 IS2 Ci VCi Figure 8-8 Operation in period D 6) Period F This pireod is the dead-time. Both Q(H) and Q(L) are in off-state. When Q(L) turns off, − IL is flowed by the energy stored in the series resonant circuit as shown in Figure 8-10. CV is discharged. When VCV decreases to VIN + VF(H), − ID(H) flows through body diode of Q(H) and VCV is clamped to VIN + VF(H). After that, Q(H) turns on. Since VDS(H) is nearly zero at the point, Q(H) operates in ZVS and ZCS. Thus, the switching loss is nearly zero. Q(H) LR OFF LP VIN ID(L) Q(L) S1 Cv ON S2 Ci Figure 8-9 Operation in period E 7) After the Period F Then, ID(H) flows and the operation returns to the period A. Q(H) The above operation is repeated, the energy is transferred to the secondary side from the resonant circuit. -ID(H) LR OFF LP VIN -IL Q(L) VCV OFF Cv Ci Figure 8-10 Operation in period F SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 11 SSC9522S Series 8.2 Startup Operation Figure 8-11 shows the VCC pin peripheral circuit with Brown-in and Brown-out Function, Figure 8-12 shows the VCC pin peripheral circuit without Brown-in and Brown-out Function (see Section 8.8 about Brown-in and Brown-out Function). The VCC pin is a power supply input pin for a control circuit and is supplied from an external power supply. In Figure 8-13, when the VCC pin increases to the Operation Start Voltage, VCC(ON) = 11.8 V, the control circuit starts operation. When the VCC pin decreases to the Operation Stop Voltage, VCC(OFF) = 9.8 V, the control circuit is stopped by Undervoltage Lockout (UVLO) circuit, and returns to the state before startup. In startup operation, the IC starts a switching operation when the IC satisfies all conditions below as shown in Figure 8-14. VCC pin voltage ≥ VCC(ON) = 11.8 V VSEN pin voltage ≥ VSEN(ON) = 1.42 V CSS pin voltage ≥ VCSS(2) = 0.59 V VCC pin voltage VCC(ON) VSEN pin voltage VSEN(ON) CSS pin voltage VCSS(2) VGL pin voltage R1 External power supply time R2 C1 U1 R3 Figure 8-14 Startup waveforms VCC 2 1 VSEN CSS GND 4 5 R4 C2 C3 C6 Figure 8-11 VCC pin peripheral circuit with Brown-in and Brown-out Function External power supply U1 C1 1 When the IC is supplied by the external power supply, tST is calculated by Equation (7). tST is the total startup time until the IC starts a switching operation after VCC pin voltage reaches VCC(ON). ● With Brown-in and Brown-out Function t ST t ST1 C6 VCSS ( 2) | I CSS ( C) | (7) where, VCSS(2) is 0.59 V and ICSS(C) is − 0.18 mA. If C6 is 1 μF, tST becomes about 3.3 ms. VCC 2 VSEN CSS GND 4 5 C2 C3 C6 Figure 8-12 VCC pin peripheral circuit without Brown-in and Brown-out Function ● Without Brown-in and Brown-out Function In this case, tST is a value of adding tST1 calculated by Equation (7) to tST2 calculated by Equation (8). The period that until the VSEN pin voltage reaches to VSEN(ON) = 1.42 V after the VCC pin voltage reaches VCC(ON) is defined as tST2. t ST 2 C2 380k Circuit current, ICC Stop VCC（OFF） (8) If C6 is 1 μF and C2 is 0.01 μF, tST1 becomes 3.3ms and tST2 becomes about 3.8 ms. Thus, tST is tST1 + tST2 = 7.1 ms. Start VCC（ON） VCC pin voltage Figure 8-13 Relationship between VCC pin voltage and ICC SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 12 SSC9522S Series 8.3 Soft Start Function Figure 8-15 shows the waveform of the CSS pin in the startup operation. The IC has Soft Start Function to reduce stress of peripheral component and prevent the capacitive mode operation. During the soft start operation, C6 connected to the CSS pin is charged by the CSS Pin Charge Current, ICSS(C) = − 0.18 mA. The oscillation frequency is varied by the CSS pin voltage. The oscillation frequency becomes gradually low with the increasing CSS pin voltage. At same time, output power increases. When the output voltage increases, the IC is operated with an oscillation frequency controlled by feedback. If the overcurrent protection activates as soon as the IC starts and the CSS pin voltage is under the CSS Pin Threshold Voltage (2), VCSS(2) = 0.59 V, the IC stops switching operation. Since the period of the high peak current of primary windings becomes short, the stress of peripheral components is reduced. When the IC becomes any of the following conditions, C6 is discharged by the CSS Pin Reset Current, ICSS(R) = 1.8 mA. When the voltage of between the VB pin and the VS pin, VB-S, increases to VBUV(ON) = 7.3 V or more, an internal high-side drive circuit starts operation. When VB-S decreases to VBUV(OFF) = 6.4 V or less, its drive circuit stops operation. In case the both ends of C10 are short, the IC is protected by VBUV(OFF). D1 should use a fast recovery diode that is short recovery time and low leakage current. AG01A (Vrm = 600 V, Sanken product) is recommended when the maximum input voltage is 265V AC. C10 should use film or ceramic capacitor that is the low ESR and the low leakage current. D1 R8 Bootstrap circuit 14 VB About 5.5V Soft start peropd VCSS(2)=0.59V C6 is charged by -0.18mA time Primary winding current Limited by OCP 0A time Q(H) 15 VGL C9 11 Cv GND 4 U1 Q(L) Ci COM 10 Figure 8-16 Bootstrap circuit Constant Output Voltage Control Figure 8-17 shows the FB pin peripheral circuit. The FB pin is sunk the feedback current by the photo-coupler, PC1, connected to FB pin. As a result, since the oscillation frequency is controlled by the FB pin, the output voltage is controlled to constant voltage (in inductance area). When the FB pin current decreases to the FB Pin Source current at Burst Mode Start, ICONT(1) = − 2.5 mA or less at light load, the IC stops switching operation. This operation reduces switching loss, and prevents the increasing of the secondary output voltage. The photo-coupler of the secondary side should be considered about the secular change of CTR and its current ability for control should be set ICONT(2) = − 3.7 mA (min.) or less. The recommend value of R6 is 560 Ω. U1 Figure 8-15 Soft start operation waveforms FB GND 3 8.4 T1 VS REG 8 8.5 OCP operation Oscillation frequency is period controlled by feedback current D2 High- side Driver ● VCC pin voltage ≤ VCC(OFF)= 9.8 V ● VSEN pin voltage ≤ VSEN(OFF)= 1.16 V ● When the latched shutdown is operated by External Latched Shutdown Function or some protection (OVP, OLP and TSD) CSS pin voltage C10 VGH 16 4 High-side Driver Figure 8-16 shows a bootstrap circuit. The bootstrap circuit is for driving to Q(H) and is made by D1, R8 and C10 between the REG pin and the VS pin. When Q(H) is OFF state and Q(L) is ON state, the VS pin voltage becomes about ground level and C10 is charged from the REG pin. C5 R5 R6 C4 PC1 Figure 8-17 FB pin peripheral circuit SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 13 SSC9522S Series 8.6 VIN Automatic Dead Time Adjustment Function Q(H) Dead time detection Reg As shown in Figure 8-18, if the dead time is shorter than the voltage resonant period, the power MOSFET is turned on and off during the voltage resonant operation. In this case, the power MOSFET turned on and off in hard switching operation, and the switching loss increases. The Automatic Dead Time Adjustment Function is the function that the ZVS (Zero Voltage Switching) operation of Q(H) and Q(L) is controlled automatically by the voltage resonant period detection of IC. The voltage resonant period is varied by the power supply specifications (input voltage and output power, etc.). However, the power supply with this function is unnecessary to adjust the dead time for each power supply specification. VGH SW2 VS T1 15 Q(L) Logic VGL 11 Cv VCV Ci SW1 COM RV 10 RC CRV 9 U1 Figure 8-19 RV pin peripheral circuit and dead time detection circuit dt Q(L) drain to source voltage, VDS(L) VGL 16 dt dv VGH Q(H) D-S voltage, VDS(H) time Dead time Differential current,Δi Loss increase by hard switching operation time Figure 8-20 Differential current waveforms Voltage resonant period Figure 8-18 ZVS failure operation waveform Figure 8-19 shows the RV pin peripheral circuit and the internal dead time detection circuit. The external components for this function is only high-voltage ceramic capacitor, CRV, connected between the VS pin and the RV pin. The value of CRV is about 5 pF. The RV pin voltage is the divided voltage by resistors between the internal reference voltage, Reg, and the GND pin. When the drain to source voltage of Q(L), VDS(L), increases, the differential current, Δi, flows through CRV (refer to Figure 8-20). The dv/dt when VDS(L) increases is detected by Δi input to the RV pin. Since SW1 and SW2 turn on necessary period, the IC circuit current reduction and the differential circuit response improvement are achieved. Δi is calculated by Equation (9). The CRV should be adjusted in all condition including transient state so that Δi satisfies Equation (10). If Δi is large, the capacitance of CRV is adjusted small. When dt is under 40 ns, Δi is ± 100 mA. dv Δi＝C RV dt 100 (mA) × 40 (ns) Δi ≤ dt (9) (10) Figure 8-21 shows the operating waveform of the Automatic Dead Time Adjustment Function. When Q(L) and Q(H) turn off, this function operates as follows: ● Q(L) turns off After Q(L) turns off, SW2 is turned on while SW1 is kept on state. The resonant current flows through CV, Ci and T1 (refer to Figure 8-19) and the CV voltage, VCV, increases from 0 V. When VCV becomes Equation (11), the resonant current flows through the body diode of Q(H) and VCV is clamped VIN + VF(H). The period that until VCV is clamped after VCV starts to increase is defined as the voltage resonant period. VCV VIN VF( H) (11) Where, VIN is input voltage and VF(H) is the forward voltage of the body diode of Q(H) In this time, the differential current, Δi, flows through CRV. The RV pin voltage increases from the voltage divided by internal resistors and becomes internal clamped voltage. When the voltage resonant period finishes and flowing Δi finishes, the RV pin voltage starts to decrease. When the RV pin voltage becomes the Voltage Resonant Detection Voltage (1), VRV(1) = 4.9 V, Q(H) is turned on and SW1 is turned off. SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 14 SSC9522S Series The period that until SW1 is turned off after SW2 is turned on is defined as the automatically adjusted dead time. ● Q(H) turns off After Q(H) turns off, SW1 is turned on while SW2 is kept on state. The resonant current flows through CV, Ci and T1 (refer to Figure 8-19) and the CV voltage, VCV, decrease from the input voltage, V IN. When VCV becomes Equation (12), the resonant current flows through the body diode of Q(L) and VCV is clamped − VF(L). The period that until VCV is clamped after VCV starts to decrease is defined as the voltage resonant period. VCV VF( L) (12) Where, VF(L) is the forward voltage of the body diode of Q(L). In this time, the differential current, Δi, flows through CRV. The RV pin voltage decreases from the voltage divided by internal resistors and becomes about the ground voltage. When the voltage resonant period finishes and flowing Δi finishes, the RV pin voltage starts to increase. When the RV pin voltage becomes the Voltage Resonant Detection Voltage (2), VRV(2) = 1.77 V, Q(L) is turned on and SW2 is turned off. The period until SW2 is turned off after SW1 is turned on is defined as the automatically adjusted dead time. Automatically adjusted dead time ON The resonant power supply is operated in the inductance area shown in Figure 8-22. In the capacitance area, the power supply becomes the capacitive mode operation (refer to Section 8.1). In order to prevent the operation, the minimum oscillation frequency is needed to be set higher than f0 on each power supply specification. However, the IC has the capacitive mode operation Detection Function kept the frequency higher than f0. Thus, the minimum oscillation frequency setting is unnecessary and the power supply design is easier. In addition, the ability of transformer is improved because the operating frequency can operate close to the resonant frequency, f0. The RC pin detects the resonant current, and the capacitive mode operation is prevented. The Capacitive Mode Operation Detection Function operations as follows: Capacitance area Inductance area ON OFF OFF Voltage resonant period Q(H) drain to source voltage, VDS(H) Q(L) drain to source voltage, VDS(L)=VCV Capacitive Mode Operation Detection Function ON OFF SW2 8.7 Impedance SW1 When the RV pin is inputted the signal of VRV(1) and VRV(2), the IC is controlled ZVS (Zero Voltage Switching) always by the Automatic Dead Time Adjustment Function. In minimum output power at maximum input voltage and maximum output power at minimum input voltage, the ZCS (Zero Current Switching) operation of IC (the drain current flows through the body diode is about 1 μs as shown in Figure 8-21), should be checked based on actual operation in the application. Operating area f0 Voltage resonant period Resonant fresuency Hard switching Sift switching RV pin voltage VRV(1) VRV(2) Uncontrollable operation Q(H) drain current, ID(H) Figure 8-22 Operating area of resonant power supply Flows through body diode about 1μs Figure 8-21 Automatic Dead Time Adjustment Function operating waveforms ● Period in which the Q(H) is ON Figure 8-23 shows the RC pin waveform in the inductance area, and Figure 8-24 shows the RC pin SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 15 SSC9522S Series waveform in the capacitance area. In the inductance area, the RC pin voltage doesn’t cross VRC = + 0.155 V in the downward direction during the on period of Q(H) as shown in Figure 8-23. On the contrary, in the capacitance area, the RC pin voltage crosses VRC = + 0.155 V in the downward direction. At this point, the capacitive mode operation is detected. Thus, Q(H) is turned off, and Q(L) is turned on, as shown in Figure 8-24. ● Period in which the Q(L) is on Contrary to the above of Q(H), in the capacitance area, the RC pin voltage crosses VRC = – 0.155 V in the upward directiont during the on period of Q(L). At this point, the capacitive mode operation is detected. Thus, Q(L) is turned off and Q(H) is turned on. changing). In addition, the RC pin voltage should be within the absolute maximum voltage ± 6 V. Since ROCP and C11 are used by Overcurrent Protection (OCP), these values should take account of OCP. If the RC pin voltage becomes more than the RC pin threshold voltage (High speed), VRC(S) = 2.35 V, or less than VRC(S) = – 2.35 V, OCP becomes active (refer to Section 8.9). VGH U1 VS VGL As above, since the capacitive mode operation is detected by pulse-by-pulse and the operating frequency is synchronized with the frequency of the capacitive mode operation, and the capacitive mode operation is prevented. C8 RC pin voltage 8.8 VRC+ 0 Figure 8-23 RC pin voltage in inductance area VDS(H) OFF ON 0 RC pin voltage VRC+ Uncontrollable operation detection 0 Figure 8-24 RC pin voltage in capacitance area In order to quicken detection speed of the capacitive mode operation, the RC pin is connected before the filter circuit of the OC pin as shown in Figure 8-25. C8 is for preventing malfunction caused by noise. The value of C8 is about 100 pF. The value of ROCP and C11 should be adjusted so that the RC pin voltage reaches to VRC = ± 0.155 V in the condition that the IC operation becomes the capacitive mode operation easily (startup operation, input voltage off, output short and dynamically output power T1 C13 C14 11 Cv ID(L) Ci 10 C12 R11 ROCP Figure 8-25 RC pin peripheral circuit OFF ON 15 ID(H) RC COM GND CSS OC RC 6 5 7 4 VDS(H) 16 Brown-in and Brown-out Function When the input voltage decreases, the switching operation of the IC is stopped by Brown-in and Brown-out Function. This function prevents excessive input current and overheats. The detection voltage of Brown-in and Brown-out Function is set by R1 to R4 shown in Figure 8-26. When the VCC pin voltage is higher than VCC(ON), this function operates depending on the VSEN pin voltage as follows: ● When the VSEN pin voltage is more than VSEN (ON) = 1.42 V, the IC starts. ● When the VSEN pin voltage is less than VSEN (OFF) = 1.16 V, the IC stops switching operation. Given, the DC input voltage when the IC starts as VIN(ON), the DC input voltage when the switching operation of the IC stops as VIN(OFF). VIN(ON) is calculated by Equation (13). VIN(OFF) is calculated by Equation (14). Thus, the relationship between VIN(ON) and VIN(OFF) is Equation (15). VIN(ON) ≒ VSEN ( ON ) R1 R 2 R3 R 4 R4 VIN(OFF) ≒ VSEN ( OFF ) VIN(OFF) ≒ V SEN ( OFF ) VSEN ( ON ) SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 R1 R 2 R3 R 4 VIN(ON) R4 (13) (14) (15) 16 SSC9522S Series The detection resistance is calculated from Equation (13) as follows: R1 R 2 R 3 ≒ VIN(ON) VSEN ( ON ) VSEN ( ON ) R4 U1 CSS 5 GND 4 (16) ● Select a resistor designed against electromigration according to the requirement of the application, or ● Use a combination of resistors in series for that to reduce each applied voltage C2 shown in Figure 8-26 is for reducing ripple voltage of detection voltage and making delay time. The value of C2 is about 0.1 μF. The value of R1 to R4 and C2 should be selected based on actual operation in the application. When the Brown-in and Brown-out Function does not be used, the detection resistance (R1, R2, R3, and R4) is removed. C2 is for preventing malfunction caused by noise. The value of C2 is about 0.01 μF. Figure 8-27 CSS pin peripheral circuit example 8.10 Overcurrent Protection (OCP) When Overcurrent Protection (OCP) is activated, the output power is limited by detecting the drain current of the power MOSFET at pulse-by-pulse. The overcurrent is detected by the OC pin or the RC pin. Figure 8-28 shows the peripheral circuit of the OC pin and the RC pin. C11 is the bypass capacitor. Since C11 is smaller than Ci, the detection current of ROCP becomes low. Thus, the ROCP can reduce loss and be small resistor. Q(H) VGH R1 VAC U1 VS 16 1 C2 11 VSEN 4 GND ID(H) Q(L) VGL R3 T1 15 U1 R2 C1 R4 VCSS(1) ≤ VCSS <12V C6 Because R1, R2, and R3 are applied high DC voltage and are high resistance, the following should be considered: External circuit GND CSS OC RCRC COM 6 7 4 5 10 Cv Ci C11 R7 Figure 8-26 VSEN pin peripheral circuit C8 ROCP C7 C6 8.9 External Latched Shutdown Function Figure 8-27 shows the CSS pin peripheral circuit example. When the voltage is inputted to the CSS pin from an external power supply, External Latched Shutdown Function is activated, the IC stops switching operation in the latch mode. When the VCC pin voltage is decreased to VCC(LA_OFF) = 8.2 V or less, the latch mode is released. This function can be used as the protection of abnormal operations. The CSS pin input voltage should be set VCSS(1) = 8.6 V (max.) or more and less than the absolute maximum ratings 12 V. Since the sink current flows from the CSS pin in the overcurrent operation (refer to Section 8.10), the current supply ability of the external circuit should be set more than the CSS pin sink current (about 100 mA). Figure 8-28 the peripheral circuit of OC pin and RC pin Since the accurate value of the resonant current cannot be calculated easy from the condition of the resonant power supply including input voltage and output voltage, the value of ROCP, C11, R7 and C7 should be adjusted based on actual operation in the application. R7 and C7 are the filter of the OC pin. The value of ROCP, C11, R7 and C7 are set as follows: ● C11 and ROCP C11 is 100pF to 330pF (around 1 % of Ci value). ROCP is around 100 Ω. Given the current of the high side power MOSFET at ON state as ID(H). ROCP is calculated Equation (17). The detection voltage of ROCP is used the detection of the capacitive mode operation (refer to Section 8.7). Therefore, setting of ROCP and C11 should be taken account of both OCP and the capacitive mode SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 17 SSC9522S Series operation. R OCP ≒ 8.11 Overload Protection (OLP) V OC ( L ) C11 I D( H ) C11 Ci (17) ● R7 and C7 are for high frequency noise reduction. R7 is 100 Ω to 470 Ω. C7 is 100 pF to 1000 pF. Table 8-1 shows the overcurrent detection voltage of the OC pin and the RC pin, and the sink current of CSS pin. There are three OCP operations as follows: 1) Low Level OCP Detection When the OC pin voltage becomes VOC(L) or more, C6 connected to the CSS pin is discharged by the sink current ICSS(L). As a result, the oscillation frequency increases, the output power is limited. If the OC pin voltage decreases less than VOC(L) during discharge of C6, the IC stops discharge of C6. 2) High Level OCP Detection When the OC pin voltage becomes VOC(H) or more, C6 is discharged by the sink current ICSS(H). Since ICSS(H) is eleven times of ICSS(L), the oscillation frequency increases at high speed, the output power is limited quickly. If the OC pin voltage decreases less than VOC(H) during discharge of C6, the IC becomes the Low Level OCP Detection. 3) High Speed OCP Detection In case the large current flows as output is shorted, this protection is activated. When the OC pin voltage or the RC pin voltage becomes as follows, the switching states of the power MOSFET is inverted. OC pin voltage is more than VOC(S) or RC pin voltage is more than |VRC(S)|. At same time, C6 is discharged by the sink current ICSS(S). As a result, the oscillation frequency increases at high speed, the output power is limited quickly. If the OC pin voltage decreases less than VOC(S) or the RC pin voltage becomes within |VRC(S)| due to reducing the output power, the IC becomes the High Speed OCP Detection and the Low Level OCP Detection. Table 8-1 Overcurrent detection voltage and sink current of CSS pin OCP Pins Low High OC OC OC High speed RC Detection voltage VOC(L) = 1.52 V VOC(H) = 1.83 V VOC(S) = 2.35 V VRC(S) = 2.35 V, – 2.35 V CSS pin sink current ICSS(L) = 1.8 mA ICSS(H) = 20.0 mA Figure 8-29 shows the FB pin peripheral circuit, Figure 8-30 shows the FB pin waveform at Overload Protection (OLP) operation. When the output power becomes overload state that the drain current is limited by Overcurrent Protection (OCP) operation, the oscillation frequency increases. When the oscillation frequency increases, the output voltage decreases and the current of the secondary photo-coupler becomes zero. Thus, the feedback current flowing through the photo-coupler connected the FB pin becomes zero. As a result, C4 is charged by the FB Pin Source Current IFB = − 25.5 μA, and the FB pin voltage increases. If the FB pin voltage increases to the FB Pin Threshold Voltage VFB = 7.05 V, the IC stops switching operation in the latch mode. When the VCC pin voltage is decreased to VCC(LA_OFF) = 8.2 V or less or the VSEN pin voltage is decreased to VSEN(OFF) = 1.16 V or less, the latch mode is released. The stresses of the power MOSFET and the secondary side rectifier diode are reduced by OLP. Given the time that until the FB pin voltage reaches to VFB as the OLP delay time, tDLY (refer to Figure 8-30). tDLY is calculated Equation (18). If R5 is 47 kΩ and C4 is 4.7 μF, tDLY becomes about 0.5 s. t DLY ≒ 4.05V R5 I C4 FB (18) I FB Where, IFB is the FB Pin Source Current − 25.5 μA. U1 FB 3 GND 4 IFB C5 R5 R6 C4 PC1 Figure 8-29 FB pin peripheral circuit FB pin voltage VFB=7.05V C7 is charged by -25.5µA About 3V The voltage of both end of R1due to flowing -25.5µA Normal operation ICSS(S) = 18.3 mA SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 OLP opetation time Latched shutdown OLP delay time, tDLY Figure 8-30 OLP operation 18 SSC9522S Series 8.12 Overvoltage Protection (OVP) When the VCC pin voltage increases to the VCC Pin OVP Threshold Voltage VCC(OVP) = 31.0 V, Overvoltage Protection (OVP) is activated and the IC stops switching operation in the latch mode. When the VCC pin voltage is decreased to VCC(LA_OFF) = 8.2 V or less or the VSEN pin voltage is decreased to VSEN(OFF) = 1.16 V or less, the latch mode is released. The VCC pin input voltage should be set absolute maximum ratings 35 V or less. 8.13 Thermal Shutdown (TSD) When the junction temperature of the IC reach to the Thermal Shutdown Temperature T j(TSD) = 150 °C (min.), Thermal Shutdown (TSD) is activated and the IC stops switching operation in the latch mode. When the VCC pin voltage is decreased to VCC(LA_OFF) = 8.2 V or less or the VSEN pin voltage is decreased to VSEN(OFF) = 1.16 V or less, the latch mode is released. ● Gate Pin Peripheral Circuit The VGH pin and the VGL pin are for the gate dive of an external power MOSFET. The source peak current of the VGH pin and the VGL pin are – 515 mA, the sink peak current of these pins are 685 mA. In Figure 9-1, RA, RB and DS should be adjusted by the loss of the power MOSFET and the gate waveform (reduction of ringing caused by pattern layout, and others) and EMI noise. RGS is for preventing malfunction caused by precipitous dv/dt when the power MOSFET turns off. The value of RGS is about 10 kΩ to 100 kΩ. RGS is connected to near the Gate pin and the Source pin. When the gate resistances are adjusted, the gate waveforms should be checked that the dead time is ensured as shown in Figure 9-2. RB DS Drain Gate RA RGS 9. 9.1 Design Notes External Components Take care to use properly rated, including derating as necessary and proper type of components. ● Input and Output Electrolytic Capacitor Apply proper derating to ripple current, voltage, and temperature rise. The electrolytic capacitor of high ripple current and low impedance types, designed for switch mode power supplies, is recommended to use. ● Resonant Transformer The resonant power supply uses the leakage inductance of transformer. Therefore, in order to reduce the effect of the eddy current and the skin effect, the wire of transformer should be used a bundle of fine litz wires. Source Figure 9-1 Peripheral circuit of power MOSFET gate High-side Gate Vth(min.) Low-side Gate Dead time Dead time Vth(min.) Figure 9-2 Dead time confirmation ● Current Detection Resistor, ROCP Choose a type of low internal inductance because a high frequency switching current flows to ROCP, and of properly allowable dissipation. ● Current Resonant Capacitor, Ci Large resonant current flows through Ci. Ci should use the polypropylene film capacitor with low loss and high current capability. In addition, Ci must be considered its frequency characteristic since high frequency current flows. SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 19 SSC9522S Series 9.2 PCB Trace Layout and Component Placement 2) Control Ground Trace Layout When large current flows into the control ground trace, the operation of IC might be affected by it. The control ground trace should be separate from the main circuit trace, and should be connected at a single point grounding as close to the GND pin as possible. Since the PCB circuit design and the component layout significantly affect the power supply operation, EMI noise, and power dissipation, the high frequency trace of PCB shown in Figure 9-3 should be designed low impedance by small loop and wide trace. 3) VCC Trace Layout This is the trace for supplying power to the IC, and thus it should be as small loop as possible. If C3 and the IC are distant from each other, placing a film capacitor Cf (about 0.1 μF to 1.0 μF) close to the VCC pin and the GND pin is recommended. 4) Peripheral Components for the IC Control These components should be placed close to the IC, and be connected to the IC pin as short as possible. Ci Figure 9-3 High frequency current loops (hatched areas) 5) Bootstrap Circuit Components These components should be connected to the IC pin as short as possible, and the loop for these should be as small as possible. In addition, the PCB circuit design should be taken account as follows: 6) Secondary side Rectifier Smoothing Circuit Trace Layout This is the trace of the rectifier smoothing loop, carrying the switching current, and thus it should be as wide trace and small loop as possible. Figure 9-4 shows the circuit design example. 1) Main Circuit Trace Layout This is the main trace containing switching currents, and thus it should be as wide trace and small loop as possible. VAC (1) Main trace should be wide trace and small loop BR1 (3) Loop of the power supply should be small R1 外部電源 C3 R2 C1 (5)Boot strap circuit trace should be small loop R4 R3 C2 VSEN 1 18 2 17 3 16 NC D1 VCC C5 GND PC1 C6 CSS C7 OC C8 C9 (4)Peripheral components for IC control should be placed close to the IC FB R7 RC REG RV ROCP 4 5 SSC9522S (2)GND trace for IC should be separate from main trace and should be connected at a single point R8 Cf R5 R6 6 15 14 13 U1 C4 NC 7 8 9 12 11 10 T1 (6) Main trace of secondary side should be wide trace and small loop D51 Q(H) C51 VGH VS D2 VB NC CV C10 D52 NC Q(L) VGL Ci C11 COM CRV C12 Figure 9-4 Peripheral circuit example around the IC SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 20 SSC9522S Series OPERATING PRECAUTIONS In the case that you use Sanken products or design your products by using Sanken products, the reliability largely depends on the degree of derating to be made to the rated values. Derating may be interpreted as a case that an operation range is set by derating the load from each rated value or surge voltage or noise is considered for derating in order to assure or improve the reliability. In general, derating factors include electric stresses such as electric voltage, electric current, electric power etc., environmental stresses such as ambient temperature, humidity etc. and thermal stress caused due to self-heating of semiconductor products. For these stresses, instantaneous values, maximum values and minimum values must be taken into consideration. In addition, it should be noted that since power devices or IC’s including power devices have large self-heating value, the degree of derating of junction temperature affects the reliability significantly. Because reliability can be affected adversely by improper storage environments and handling methods, please observe the following cautions. Cautions for Storage ● Ensure that storage conditions comply with the standard temperature (5 to 35°C) and the standard relative humidity (around 40 to 75%); avoid storage locations that experience extreme changes in temperature or humidity. ● Avoid locations where dust or harmful gases are present and avoid direct sunlight. ● Reinspect for rust on leads and solderability of the products that have been stored for a long time. Cautions for Testing and Handling When tests are carried out during inspection testing and other standard test periods, protect the products from power surges from the testing device, shorts between the product pins, and wrong connections. Ensure all test parameters are within the ratings specified by Sanken for the products. Soldering ● When soldering the products, please be sure to minimize the working time, within the following limits: 260 ± 5 °C 10 ± 1 s (Flow, 2 times) 380 ± 10 °C 3.5 ± 0.5 s (Soldering iron, 1 time) ● Soldering should be at a distance of at least 1.5 mm from the body of the products. Electrostatic Discharge ● When handling the products, the operator must be grounded. Grounded wrist straps worn should have at least 1MΩ of resistance from the operator to ground to prevent shock hazard, and it should be placed near the operator. ● Workbenches where the products are handled should be grounded and be provided with conductive table and floor mats. ● When using measuring equipment such as a curve tracer, the equipment should be grounded. ● When soldering the products, the head of soldering irons or the solder bath must be grounded in order to prevent leak voltages generated by them from being applied to the products. ● The products should always be stored and transported in Sanken shipping containers or conductive containers, or be wrapped in aluminum foil. SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 21 SSC9522S Series IMPORTANT NOTES ● The contents in this document are subject to changes, for improvement and other purposes, without notice. Make sure that this is the latest revision of the document before use. ● Application examples, operation examples and recommended examples described in this document are quoted for the sole purpose of reference for the use of the products herein and Sanken can assume no responsibility for any infringement of industrial property rights, intellectual property rights, life, body, property or any other rights of Sanken or any third party which may result from its use. ● Unless otherwise agreed in writing by Sanken, Sanken makes no warranties of any kind, whether express or implied, as to the products, including product merchantability, and fitness for a particular purpose and special environment, and the information, including its accuracy, usefulness, and reliability, included in this document. ● Although Sanken undertakes to enhance the quality and reliability of its products, the occurrence of failure and defect of semiconductor products at a certain rate is inevitable. Users of Sanken products are requested to take, at their own risk, preventative measures including safety design of the equipment or systems against any possible injury, death, fires or damages to the society due to device failure or malfunction. ● Sanken products listed in this document are designed and intended for the use as components in general purpose electronic equipment or apparatus (home appliances, office equipment, telecommunication equipment, measuring equipment, etc.). When considering the use of Sanken products in the applications where higher reliability is required (transportation equipment and its control systems, traffic signal control systems or equipment, fire/crime alarm systems, various safety devices, etc.), and whenever long life expectancy is required even in general purpose electronic equipment or apparatus, please contact your nearest Sanken sales representative to discuss, prior to the use of the products herein. The use of Sanken products without the written consent of Sanken in the applications where extremely high reliability is required (aerospace equipment, nuclear power control systems, life support systems, etc.) is strictly prohibited. ● When using the products specified herein by either (i) combining other products or materials therewith or (ii) physically, chemically or otherwise processing or treating the products, please duly consider all possible risks that may result from all such uses in advance and proceed therewith at your own responsibility. ● Anti radioactive ray design is not considered for the products listed herein. ● Sanken assumes no responsibility for any troubles, such as dropping products caused during transportation out of Sanken’s distribution network. ● The contents in this document must not be transcribed or copied without Sanken’s written consent. SSC9522S - DSE Rev.1.2 SANKEN ELECTRIC CO.,LTD. Sept.10, 2015 http://www.sanken-ele.co.jp/en © SANKEN ELECTRIC CO.,LTD. 2010 22