| 摘要 |
A buck-boost regulation methodology operable, in one embodiment, with a single inductor, four-switch (S1-S4) buck-boost regulator configured for DCM. Buck-boost transition switching control is operable when inductor charge time exceeds a max charge time, and inductor discharge time exceeds a max discharge time, and includes: (a) during charge transition cycles, at the end of the max charge time, if IL is less than a predetermined peak current IL—MAX, switching S2 on (grounding the output side of the inductor) and S4 off, causing IL to increase (a rapid S1S2 charging current ramp), until IL reaches IL—MAX, and (b) during discharge transition cycles, at the end of the max charge time, if IL is greater than zero, switching S1 off and S3 on (grounding the input side of the inductor), causing IL to increase (a rapid S3S4 IL discharging current ramp), until IL reaches zero. |
| 主权项 |
1. A buck-boost switching converter circuit for converting input power from an input power source into regulated output power supplied to a load, comprising:
a switching network coupled to first and second inductor nodes and an output node; the first and second inductor nodes configured to couple to respectively first and second ends of an inductor, and the output node configured to couple to an output capacitor and in parallel to the load; the switching network including: (i) a switch S1 configured to couple to the input power source, and coupled to the first inductor node, (ii) a switch S2 coupled between the second inductor node and ground, (iii) a rectification component S3 coupled between the first inductor node and ground and configured to conduct forward current in a forward direction, and block reverse current in a reverse direction, and (iv) a rectification component S4 coupled between the second inductor node and the output node, and configured to conduct forward current from the second inductor node to the output node and to block reverse current from the output node to the second inductor node; a switching controller configured to control the switching network to control inductor current IL, including inductor charge and discharge, to provide power conversion in three modes:
a buck mode providing down conversion when the input power is greater than the regulated output power by a buck transition parameter corresponding to a predetermined max charge time;a boost mode providing up conversion when the input power is less than the regulated output power by a boost-transition parameter corresponding to a predetermined max discharge time; anda transition mode enabled when the difference between the input power and the regulated output power corresponds to a buck-boost transition condition as represented by an inductor charge time that exceeds the max charge time, and an inductor discharge time the exceeds the max discharge time, the transition mode comprising transitioning between charge and discharge transition cycles in which:
during the charge cycle, the switching controller controls charging the inductor by (i) switching S1 on and S2 off, with the rectification component S3 configured to block reverse current from the input power source to ground, such that inductor current IL charges the inductor with an S1S4A IL current ramp, (ii) determining, at the end of the max charge time, that IL is less than a predetermined peak current IL—MAX, and in response (iii) switching S2 on to ground the second inductor node (rectification component S4 blocking any reverse current from the output node to the second inductor node), so that IL increases to an S1S2 IL current ramp greater in magnitude than the S1S4A IL current ramp, until IL reaches IL—MAX; andduring the discharge cycle, the switching controller controls discharging the inductor by: (i) switching S1 on and S2 off, with the rectification component S3 configured to block reverse current from the input power source to ground, such that the inductor discharges with an S1S4B IL current ramp, (ii) determining, at the end of the max discharge time, that IL is greater than zero, and in response (ii) switching S1 off, with the rectification component S3 configured to connect the first inductor node to ground, so that IL increases to an S3S4 IL current ramp greater in magnitude than the S1S4A IL current ramp, until IL reaches zero. |
