The invention discloses a primary edge control type switch power supply with high-precision constant-
voltage / constant-current output and a high-pulse-frequency (PF) value. The primary edge control type switch power supply comprises an
electromagnetic interference and filtering circuit, a rectifying filtering circuit, a
transformer, a
voltage stabilizing buffer circuit, a filtering shaping output circuit, a
metal oxide semiconductor (MOS) tube, a sampling
resistor and a constant-
voltage and constant-
current pulse frequency control (PFC) driving module, wherein the voltage stabilizing buffer circuit, the filtering shaping output circuit, the MOS tube, the sampling
resistor and the constant-voltage and constant-current PFC driving module are connected in parallel with the
transformer. The primary edge control type switch power supply has the advantages that the
transformer primary edge is detected and is fed back to a PFC control
chip, and a
pulse frequency modulation (PFM) mode is adopted, so high-precision current and voltage can be output. Compared with the traditional
driving circuit, the primary edge control type switch power supply has the advantages that
peripheral devices such as optical couplers and the like are omitted, so a
peripheral circuit is simpler, the PF value and the electric work efficiency of the whole power supply are obviously improved, and the primary edge control type switch power supply has the obvious characteristics that the periphery circuit is simple, the cost is low, and the performance is high. The large-scale popularization and application can be easily realized.