AN8038S Panasonic Semiconductor, AN8038S Datasheet
AN8038S
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AN8038S Summary of contents
Page 1
... RCC local resonance circuit for improved conformance with energy conservation laws Overview The AN8038 and AN8038S are self-excited AC-DC switching power supply control IC that adopt RCC local resonance control. These ICs are designed to achieve high efficiency over a wide range of loads (light loads at the ...
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... AN8038, AN8038S Block Diagram OVP OVP RSTB 17 I/V FB IFB conv. 4.2 V High-side Current clamp reviser (ITR Low-side clamp 0. Start INIT R Stop S (SD latch) Q Current reviser (IFB) 1 (TR latch) Voltage Regulators V REF Out ...
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... Absolute Maximum Ratings Parameter Supply voltage Peak output current Power dissipation AN8038 (Independent IC without a heat sink) AN8038S Operating temperature Storage temperature Note When mounted on a printed circuit board: 477 When mounted on a printed circuit board: 191 mW Recommended Operating Range Parameter ...
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... AN8038, AN8038S Electrical Characteristics at V Parameter Low voltage protection (U.V.L.O.) initial startup supply voltage. Low voltage protection (U.V.L.O.) operation stop supply voltage Overvoltage protection (OVP) operating supply voltage Overvoltage protection (OVP) release supply voltage Overvoltage protection (OVP) operating time circuit current 1 Overvoltage protection (OVP) ...
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... When a transformer reset is detected, i.e., a low level is input to this pin, the IC output goes high. However, the transformer reset signal is ignored if the signal is shorter than the minimum off- period determined by the C the maximum on-period is corrected according to the source current. AN8038, AN8038S Min Typ Max 5.4 0.1 1 000 pF 4 ...
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... AN8038, AN8038S Terminal Equivalent Circuits (continued) Pin No. Equivalent Circuit 2 V REF Comp REF Comp REF REF Comp. CLM 6 GND 6 6 RSTB: Adjusts the light-load detection level that deter- mines the time when the IC switches from RCC to discontinuous operation ...
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... This pin monitors supply voltage and has the 8 threshold for the start, stop, OVP, and OVP reset levels. ripple. Insert a capacitor near the IC Allowable V ripple range CC Recommended operating range 70 100 300 1 000 10 V ripple frequency (kHz) CC AN8038, AN8038S Description I/O and GND pins to reduce CC 10 000 I 7 ...
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... AN8038, AN8038S Application Notes [1] Timing charts Circuit diagram (B) CLM Normal control waveforms (A) Bias winding voltage 0 V Off (B) TR pin voltage 0 V 4.2 V (C) CF pin voltage V RSTB Can be modified with an external resistor (D) Out pin voltage V 1 Off 0 V (F) Secondary Winding current winding current ...
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... Winding current 0 A Light (G) CLM pin voltage 0 V 205 mV CLM threshold voltage On Off On Off Rapid charging during CLM operation On Off On Off Primary Secondary winding winding current current Load AN8038, AN8038S On Off On On Off On On-period limitation during CLM operation Heavy Overcurrent detection 9 ...
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... AN8038, AN8038S Application Notes (continued) [2] Operation descriptions 1. Start/stop circuit block Startup mechanism After the AC voltage is applied and the supply voltage due to the current in the startup resistor reaches the startup voltage and the IC begins to operate, drive of the power MOSFET begins. This causes a bias in the transformer, and the supply voltage is provided to the IC from the bias winding ...
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... Figure 2. On-period block diagram and control waveforms TR1 V Current mirror Out 280 A GND I ON typ Input voltage correction pin voltage RSTB On-period AN8038, AN8038S TR2 larger On-period: shorter Off-period 11 ...
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... AN8038, AN8038S Application Notes (continued) [2] Operation descriptions (continued) 2. Oscillator circuit (continued) Notes on switching from RCC operation to discontinuous operation When the state changes from normal load to standby mode, the post-I-V conversion output monitor voltage V increases along with the increase of the amount of feedback current. Then, when the IFB pin feedback current ...
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... A) IFB (I 250 A) 0.7 V IFB 250 A) IFB RSTB CFL OFF 0.7 V typ RSTB ( 4.2 V typ.) FB RSTB AN8038, AN8038S 0.2 V (typical CFL RSTB V 4.2 V typ. CFH V 3.5 V typ. RSTB IFB 1 mA IFB 1 mA IFB time determined by C OFF 4.2 CFH . CF 13 ...
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... Operation descriptions (continued) 3. Local resonance operation (power MOSFET turn on delay circuit) The AN8038 and AN8038S transformer reset detection functions detect a low-level input to the TR pin. (This is similar to earlier Panasonic ICs, in particular the AN8026, AN8027, AN8028, and AN8029.) Local resonance operation is possible with circuits as shown in figure the resonance capacitor, and R9 and C9 form a delay circuit for adjusting the power MOSFET turn on time ...
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... The peak voltage when the voltage is negative The peak voltage when the voltage is positive changing the value consideration of the resonance capacitance and AN8038, AN8038S 1.5 V typ. 0.15 V typ that is the time between ...
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... AN8038, AN8038S Application Notes (continued) [2] Operation descriptions (continued) 4. Power supply output control system (IFB: feedback) Constant-voltage control of the power supply output is conducted by changing the on- and off-periods of the power MOSFET. On- and off-periods are controlled as follows: a feedback current responding to the output of output-voltage detection circuit formed at secondary output side is input to IFB pin through a photocoupler ...
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... MOSFET reliably. Rectified IFB PC1 R3 C4 Out CLM R8 C6 Figure 8 AN8038, AN8038S ) flows from the IFB pin into C4 due to this IFB becomes smaller with IFB Startup resistor Since ON 17 ...
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... AN8038, AN8038S Application Notes (continued) [2] Operation descriptions (continued) 5. Output block (continued) The main requirement on the control IC in this type of power supply is the ability to provide a large peak current. That is to say, a high average current is not required in steady state operation. This is because the power MOSFET is a capacitive load, and while a large peak current is required to drive such a load rapidly, once the load has been charged or discharged a much smaller current suffices to retain that state ...
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... IC as much as possible 1.7 mA typ. 0.53 mA typ. 7 Figure 11. OVP operating circuit current 25 C. While this control operation is repeated CLM GND To AC Figure 12 AN8038, AN8038S Use a capacitor with excellent frequency characteristics. R7 Use resistors with no inductance. 19 ...
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... AN8038, AN8038S Application Notes (continued) [2] Operation descriptions (continued) 5. Output block (continued) Overcurrent protection circuit (input voltage correction function extended application, this section presents a circuit design that applies a correction so that the overcurrent protection operating point is held fixed with respect to variations in the input voltage. This circuit uses the proportional relationship between the input voltage and the inverted voltage of the bias winding, and superposes inverted voltage of the bias winding on the overcurrent protection operating voltage ...
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... V OUT I FB and GND not Reverse voltage Forward current (average 200 500 mA AN8038, AN8038S Rectified Out Figure Figure 16 Forward current (peak) 150 mA 300 GND Control pin ...
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... AN8038, AN8038S Application Circuit Examples Application circuit example 1 RSTB 2 IFB Application circuit example C12 MA2C700 (MA700 ) AN8038, AN8038S C11 1 000 pF 0.015 MA2C700 (MA700 ) Out 7 GND 6 CLM 180 R16 ...