14.1.1.1 Definition of Terms

Capacitance Terms in Farads

• C_BULK: total input capacitance of C_B1 and C_B2.
• C_VDD: capacitance on the VDD terminal.
• C_OUT: output capacitance.

Duty Cycle Terms

• K_CC: secondary diode conduction duty cycle in CC, (see Electrical Characteristics).
• D_MAX: MOSFET on-time maximum duty cycle.

Frequency Terms in Hertz

• f_LINE: minimum line frequency.
• f_TARGET(max): target full-load maximum switching frequency of the converter.
• f_MIN: minimum switching frequency of the converter, add 15% margin over the f_SW(min) limit of the device.
• f_SW(min): minimum switching frequency (see Electrical Characteristics)

Current Terms in Amperes

• I_OCC: converter output current target when operating in constant current mode.
• I_{D_PK(max)}: maximum transformer primary current peak.
• I_TRAN: required positive load-step current.
• I_RUN: maximum current consumption of the device (see Electrical Characteristics).
• I_VSLRUN: VS terminal run current (see Electrical Characteristics).

Current and Voltage Scaling Terms

• K_AM: maximum-to-minimum peak-primary current ratio (see Electrical Characteristics).

Transformer Terms

• L_P: transformer primary inductance.
• N_PA: transformer primary-to-auxiliary turns ratio.
• N_PS: transformer primary-to-secondary turns ratio.

Power Terms in Watts

• P_IN: converter maximum input power.
• P_INTRX: transformer maximum input power.
• P_OUT: full-load output power of the converter.
• P_SB: total stand-by input power.

Resistance Terms in Ω

• R_IPK: primary current programming resistance.
• R_ESR: total ESR of the output capacitors.
• R_PRL: preload resistance on the output of the converter.
• R_S1: high-side VS terminal resistance.
• R_S2: low-side VS terminal resistance.

Timing Terms in Seconds

• t_DMAG(min): minimum secondary rectifier conduction time.
• t_ON(min): minimum MOSFET on time.
• t_R: resonant frequency during the DCM (discontinuous conduction mode) time.

Voltage Terms in Volts

• V_BULK: highest bulk capacitor voltage for stand-by power measurement.
• V_BULK(min): minimum voltage on C_B1 and C_B2 at full power.
• V_CCR: constant-current regulating voltage (see Electrical Characteristics).
• V_OΔ: output voltage drop allowed during the load-step transient.
• V_DSPK: peak MOSFET drain-to-source voltage at high line.
• V_F: secondary rectifier, D_OUT, forward voltage drop at near-zero current.
• V_FA: auxiliary rectifier, D2, forward voltage drop.
• V_OCV: regulated output voltage of the converter, V_OUT in CV mode.
• V_VDD: voltage value on VDD terminal.
• V_OCC: target lowest converter output voltage in constant-current regulation.
• V_REV: peak reverse voltage on the secondary rectifier, D_OUT.
• V_RIPPLE: output peak-to-peak ripple voltage at full-load.
• V_VSR: CV regulating level at the VS input (see Electrical Characteristics).
• ΔV_UVLO: VDD_ON – VDD_OFF (see Electrical Characteristics).

AC Voltage Terms in V_RMS

• V_IN(max): maximum AC input voltage to the converter.
• V_IN(min): minimum AC input voltage to the converter.
• V_IN(run): converter input start-up (run) AC voltage.

Efficiency Terms

• η: converter overall efficiency.
• η_XFMR: transformer primary-to-secondary power transfer efficiency.