MP6909GJ-Z

MP6909 Fast Turn-Off Intelligent Rectifier with Turn On Slew Rate Detection The Future of Analog IC Technology DESCRIPTION FEATURES The MP6909 is a low-drop diode emulator IC that, when combined with an external switch, replaces Schottky diodes in high-efficiency flyback converters. The MP6909 regulates the forward drop of an external synchronous rectifier (SR) MOSFET to about 40mV, which switches off once the voltage becomes negative.   The MP6909 can generate its own supply voltage via an internal linear regulator. Programmable ringing detection circuitry prevents the MP6909 from turning on falsely at VDS oscillations during discontinuous conduction mode (DCM) and quasi-resonant operation. The MP6909 is available in a space-saving TSOT23-6 package.        Supplied Voltage Internally Regulated Ringing Detection Prevents False Turn-On during DCM and Quasi-Resonant Operations Works with Standard and Logic Level SR MOSFETs Compatible with Energy Star ~30ns Fast Turn-Off and Turn-On Delay ~100µA Quiescent Current Supports DCM, CCM, and Quasi-Resonant Operations Supports both High-Side and Low-Side Rectification Available in a TSOT23-6 Package APPLICATIONS    USB PD Quick Chargers Adaptors Flyback Converters All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For MPS green status, please visit the MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION MP6909 Rev. 1.0 3/6/2018 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 1 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER ORDERING INFORMATION Part Number* MP6909GJ Package TSOT23-6 Top Marking See Below * For Tape & Reel, add suffix –Z (e.g.: MP6909GJ–Z). TOP MARKING BDR: Product code of MP6909GJ Y: Year code PACKAGE REFERENCE TOP VIEW TSOT23-6 MP6909 Rev. 1.0 3/6/2018 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 2 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance SL to VSS ....................................-0.3V to +6.5V VR, VG to VSS .............................-0.3V to +14V VD, VIN to VSS ..............................-1V to +180V (2) Continuous power dissipation (TA = +25°C) ................................................................. 0.56W Junction temperature ................................150°C Lead temperature (solder) ........................260°C Storage temperature ............... -55°C to +150°C TSOT23-6 ............................. 220 .... 110 ... °C/W Recommended Operation Conditions (3) VR to VSS ........................................... 4V to 13V VD, VIN, to VSS .............................-1V to +150V Maximum junction temp. (TJ) ....................125°C MP6909 Rev. 1.0 3/6/2018 (4) θJA θJC NOTES: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ(MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD(MAX)=(TJ(MAX)TA)/θJA. Exceeding the maximum allowable power dissipation produces an excessive die temperature, causing the regulator to go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 3 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER ELECTRICAL CHARACTERISTICS VR = 9V, -40°C ≤ TJ ≤ +125°C, unless otherwise noted. Parameter Supply Management Section VR UVLO rising VR UVLO hysteresis VR maximum charging current VR regulation voltage Symbol IVR Operating current Quiescent current Shutdown current Control Circuitry Section Forward regulation voltage (VSS - VD) Turn-on threshold (VDS) Turn-off threshold (VSS - VD) Turn-on delay Turn-off delay Turn-on blanking time Turn-off blanking exit threshold Turn-off threshold during turnon blanking Turn-on slew rate detection timer Gate Driver Section VG (low) VG (high) Maximum source current (5) Maximum sink current (5) Pull-down impedance ICC Iq(VR) ISD(VR) Conditions VR = 7V, VIN = 40V VIN = 12V VR = 9V, CLOAD = 2.2nF, FSW = 100kHz VR = 5V, CLOAD = 2.2nF, FSW = 100kHz VR = 14V VR = UVLO - 0.1V Vfwd TDon TDoff TB-ON VB-OFF CLOAD = 2.2nF CLOAD = 2.2nF CLOAD = 2.2nF TSLEW RSLEW = 400k VG-L VG-H ILOAD = 10mA ILOAD = 0 Same as VG (low) Min Typ Max Units 3.55 0.1 3.75 0.2 70 9 3.95 0.3 9.5 V V mA V 2.9 3.5 mA 1.72 2.1 mA 105 135 100 µA µA 25 40 55 mV -115 -6 -86 3 30 25 1.1 -57 12 50 45 1.45 3 mV mV ns ns µs V 1.3 1.8 2.1 V 51 76 101 ns 0.01 VR 0.5 3 1 0.02 V V A A Ω 8.5 0.75 2 2 NOTE: 5) Guaranteed by characterization and design. MP6909 Rev. 1.0 3/6/2018 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 4 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER TYPICAL PERFORMANCE CHARACTERISTICS Quiescent Current vs. Temperature Operating Current vs. Temperature VR = 9V, CLOAD = 2.2nF, FSW = 100kHz VR = 14V 114 3 2.95 112 2.9 110 2.8 IQ (uA) ICC (mA) 2.85 2.75 2.7 108 106 2.65 2.6 104 2.55 2.5 102 -50 -25 0 25 50 75 100 125 -50 -25 TEMPERATURE(°C) 0 25 50 75 TEMPERATURE (°C) 100 Turn-On Delay vs. Temperature Turn-Off Delay vs. Temperature VR = 9V, CLOAD = 2.2nF VR = 9V, CLOAD = 2.2nF 45 125 35 40 30 TDOFF (ns) TDON (ns) 35 30 25 25 20 20 15 15 10 10 -50 -25 0 25 50 75 TEMPERATURE (°C) 100 -50 125 -25 0 25 50 75 TEMPERATURE (°C) 100 125 Turn-On Slew Rate Detection Timer vs. Temperature Forward Regulation Voltage (VSS VD) vs. Temperature RSLEW = 400kΩ 147 50 48 146 145 44 TSLEW (ns) VFWD (mV) 46 42 40 38 144 143 142 36 34 141 32 140 30 -50 MP6909 Rev. 1.0 3/6/2018 -25 0 25 50 75 TEMPERATURE (°C) 100 125 -50 -25 0 25 50 75 TEMPERATURE (°C) www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 100 125 5 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER TYPICAL PERFORMANCE CHARACTERISTICS (continued) VR Maximum Charging Current vs. Temperature   VR = 7V, VIN = 40V 100 90 IVR (mA) 80 70 60 50 40 -50   -25 0 25 50 75 TEMPERATURE (°C) 100 125     MP6909 Rev. 1.0 3/6/2018 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 6 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER TYPICAL PERFORMANCE CHARACTERISTICS (continued) Operation in 36W Flyback Application Operation in 36W Flyback Application VIN = 110VAC, VOUT = 12V, IOUT = 3A VIN = 220VAC, VOUT = 12V, IOUT = 3A CH1: VDS 50V/div. CH1: VDS 20V/div. CH3: VR 5V/div. CH2: VGS 5V/div. CH3: VR 5V/div. CH2: VGS 10V/div. 10μs/div. MP6909 Rev. 1.0 3/6/2018 20μs/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 7 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER PIN FUNCTIONS Pin # 1 2 Name VIN VSS 3 SL 4 5 6 VR VG VD MP6909 Rev. 1.0 3/6/2018 Description Internal linear regulator input. Ground. VSS is also used as a MOSFET source sense reference for VD. Programming for turn-on signal slew rate detection. SL prevents the SR controller from turning on falsely by ringing below the turn-on threshold at VD in discontinuous conduction mode (DCM) and quasi-resonant mode. Any signal slower than the pre-set slew rate cannot turn on VG. Internal linear regulator output. VR is the supply of the MP6909. Gate drive output. MOSFET drain voltage sense. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 8 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER BLOCK DIAGRAM Figure 1: Functional Block Diagram MP6909 Rev. 1.0 3/6/2018 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 9 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER OPERATION The MP6909 supports operation in discontinuous conduction mode (DCM), continuous conduction mode (CCM), and quasiresonant flyback converters. The control circuitry controls the gate in forward mode and turns the gate off when the synchronous rectification (SR) MOSFET current drops to zero. the turn-on blanking time, VGS is pulled low immediately. Conduction Phase When VDS rises above the forward voltage drop (-40mV) according to the decrease of the switching current, the MP6909 lowers the gate voltage level to enlarge the on resistance of the synchronous MOSFET. VR Generation VIN is the input of the internal linear regulator. VR is the output of the internal linear regulator. The capacitor at VR supplies power for the IC. When VIN < 9.3V, the internal linear regulator regulates VR at VIN-0.3V. When VIN > 9.3V, the internal linear regulator regulates VR at 9V. Start-Up and Under-Voltage Lockout (UVLO) When VR rises above 3.75V, the MP6909 exits under-voltage lockout (UVLO) and is enabled. The MP6909 enters sleep mode, and VGS is kept low once VR drops below 3.55V. Turn-On Phase When VDS drops to ~2V, a turn-on timer begins to count. This turn-on timer can be programmed by an external resistor on SL. If VDS reaches the -86mV turn-on threshold from 2V within the time (TSLEW) set by the timer, the MOSFET is turned on after a turn-on delay (about 30ns) (see Figure 2). If VDS crosses -86mV after the timer ends, the gate voltage (VG) remains off. This turn-on timer prevents the MP6909 from turning on falsely due to ringing from DCM and quasiresonant operations. TSLEW can be programmed with Equation (1): TSLEW  R SLEW  76ns 400k (1) Turn-On Blanking The control circuitry contains a blanking function. When the MOSFET turns on, the control circuit ensures that the on state lasts for a specific period of time. The turn-on blanking time is ~1.1µs to prevent an accidental turn-off due to ringing. However, if VDS reaches the turn-off threshold during turn-on blanking within MP6909 Rev. 1.0 3/6/2018 Figure 2: Turn-On/Turn-Off Timing Diagram With this control scheme, VDS is adjusted to be around -40mV even when the current through the MOSFET is fairly low. This function keeps the driver voltage at a very low level when the synchronous MOSFET is turned off, which boosts the turn-off speed and is especially important for CCM operation. Turn-Off Phase When VDS rises to trigger the turn-off threshold (-3mV), the gate voltage is pulled to zero after a very short turn-off delay of 25ns (see Figure 2). Turn-Off Blanking After the gate driver (VGS) is pulled to zero by VDS reaching the turn-off threshold (-3mV), a turn-off blanking time is applied, during which the gate driver signal is latched off. The turn-off blanking is removed when VDS rises above the turn-off blanking exit threshold (2 - 3V) (see Figure 2). www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 10 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER APPLICATION INFORMATION Slew Rate Detection Function In DCM operations, the demagnetizing ringing may bring VDS down below 0V. If VDS reaches the turn-on threshold during the ringing, SR controllers without the slew rate detection function may turn on the MOSFET by mistake. Figure 3 shows the waveform of this false turnon situation. This increases power loss and may also lead to shoot-through if the primary side MOSFET is turned on within the turn-on blanking time. External Resistor on VD Since over-voltage conditions may damage the device, there must be appropriate application designs to guarantee safe operation, especially on the high-voltage pin. A common over-voltage condition is where the body diode of the SR MOSFET is turned on and the forward voltage drop may exceed the negative rating on VD. In this case, an external resistor should be placed between VD and the MOSFET drain. Generally, the resistance is recommended to be no less than 300Ω. On the other hand, this resistor cannot be too large, since large resistor values slow down the slew rate on VDS detection. Generally, it is not recommended to use any resistance value larger than 1kΩ but should be checked based on the slew rate for each practical case. Typical System Implementations Figure 5 shows the typical system implementation for the IC power supply derived from the output voltage, which is available in low-side rectification. Figure 3: False Turn-On (without Slew Rate Detection) Considering that the slew rate of the ringing is always much less than when the primary MOSFET is actually turned off, this false turnon situation can be prevented by the slew rate detection function (see Figure 4). When the slew rate is less than the threshold set by RSLEW, the IC does not turn on the gate even when VDS reaches the turn-on threshold. Figure 5: MP6909 in Low-Side Rectification Figure 6 shows the circuit configuration for the auxiliary winding solution for the MP6909 used in high-side rectification. Figure 4: Preventing a False Turn-On (with Slew Rate Detection) MP6909 Rev. 1.0 3/6/2018 Figure 6: MP6909 in High-Side Rectification www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 11 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER SR MOSFET Selection Power MOSFET selection is a tradeoff between the RDS(ON) and QG. To achieve higher efficiency, a MOSFET with a smaller RDS(ON) is preferred. Typically, QG is larger with a smaller RDS(ON), which makes the turn-on/turn-off speed lower and leads to larger power loss and driver loss. Because VDS is adjusted at about -40mV during the driving period when the switching current is fairly small, a MOSFET with an RDS(ON) that is too low is not recommended because the gate driver is pulled low when VDS = -ISD x RDS(ON) becomes larger than -40mV. The MOSFET’s RDS(ON) does not contribute to the conduction loss. The conduction loss is PCON = -VDS x ISD ≈ ISD x 40mV. To achieve fairly high use of the MOSFET’s RDS(ON), the MOSFET should be turned on completely for at least 50% of the SR conduction period. Calculate VDS with Equation (2): VDS   I C  RDS ( ON )   I OUT / D  RDS ( ON )  V fwd (2) Where VDS is drain-source voltage of the MOSFET, D is the duty cycle of the secondary side, IOUT is output current, and Vfwd is the forward voltage threshold (~40mV). Slew Rate Set-Up Select the slew rate set-up resistor carefully. Before placing a resistor on SL, measure the VDS slew rate during normal turn-on and oscillation during DCM. Choose a resistor that can guarantee a normal SR driver turn-on. For example, if the VDS slew rate is -1V/ns during the normal drop and 0.01V/ns in oscillation, a 0.1V/ns slew rate is a proper target to set up. PCB Layout Guidelines Efficient PCB layout is critical for stable operation. For best results, refer to Figure 8, Figure 9, Figure 10, and follow the guidelines below. Sensing for VD/VSS 1. Make the sensing connection (VD/VSS) as close as possible to the MOSFET (drain/source). 2. Make the sensing loop as small as possible. 3. Keep the IC out of the power loop to prevent the sensing loop and power loop from interrupting each other (see Figure 8). Figure 7 shows the typical waveform of a flyback application. Assume it has a 50% duty cycle. The MOSFET’s RDS(ON) is recommended to be no lower than ~20/IOUT (mΩ). For a 5A application, the RDS(ON) should be no lower than 4mΩ. Figure 8: Voltage Sensing for VD/VSS 4. Place a decoupling ceramic capacitor from VR to PGND close to the IC for adequate filtering. Figure 7: Synchronous Rectification Typical Waveforms in a Flyback Application MP6909 Rev. 1.0 3/6/2018 Gate Driver Loop 1. Make the gate driver loop as small as possible to minimize the parasitic inductance. 2. Keep the driver signal far away from the VD sensing trace on the layout. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 12 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER Layout Example Figure 9 shows a layout example of a single layer with a through-hole transformer and a TO220 package SR MOSFET. RSN and CSN are the RC snubber network for the SR MOSFET. The sensing loop (VD and VSS to the SR MOSFET) is minimized and kept separate from the power loop. The VR decoupling capacitor (C2) is placed beside VR. Figure 10 shows another layout example of a single layer with a PowerPAK/SO8 package SR MOSFET, which also has a minimized sensing loop and power loop to prevent the loops from interfering with one another. 6 5 4 1 2 3 Figure 10: Layout Example with PowerPAK/SO8 SR MOSFET Figure 9: Layout Example with TO220 Package SR MOSFET MP6909 Rev. 1.0 3/6/2018 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 13 MP6909 – FAST TURN-OFF INTELLIGENT RECTIFIER PACKAGE INFORMATION TSOT23-6 NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP6909 Rev. 1.0 7/31/2018 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2018 MPS. All Rights Reserved. 14