| US 7,605,574 B2 | ||
| Switching regulator circuits | ||
| David Dearn, Wiltshire (United Kingdom); and Holger Haiplik, Swindon (United Kingdom) | ||
| Assigned to Wolfson Microelectronics plc, Edinburgh (United Kingdom) | ||
| Filed on Apr. 16, 2007, as Appl. No. 11/785,227. | ||
| Claims priority of application No. 0608192.1 (GB), filed on Apr. 26, 2006. | ||
| Prior Publication US 2007/0252567 A1, Nov. 01, 2007 | ||
| Int. Cl. G05F 1/40 (2006.01) | ||
| U.S. Cl. 323—284 [323/282; 363/21.17] | 32 Claims |
| 1. A current-mode switching regulator comprising at least: an inductor; a main switch for controlling the current flow through the inductor; and a feedback control circuit for operating the main switch cyclically and to vary a duty cycle of the main switch so as to substantially maintain an output voltage of the regulator at a desired level, said feedback control circuit further including slope compensation circuitry for introducing an offset into a comparison between a signal representing the fed-back output error voltage and a signal representing the inductor current, wherein said regulator further comprises current limiting circuitry for controlling said main switch responsive to a current limit reference signal, said current limit circuitry comprising adjustment circuitry for adjusting said current limit reference signal in response to the duty cycle of more than one previous cycle so as to limit current in the inductor irrespective of said output voltage and to a value which, in the steady state, is substantially independent of the duty cycle. |