Borrowing operations

The callable surface for troves. Concept: Open a trove and Adjust, repay, close. Mechanics: Interest model, Rates vs. utilization.

All functions are on the branch's BorrowerOperations. Approve the collateral token to that contract before any call that pulls collateral.

Open

BorrowerOperations.openTrove(
    uint256 _collateralAmount,   // collateral deposited (token units)
    uint256 _RDAmount,           // net debt minted (1,800 RD floor)
    address _upperHint,
    address _lowerHint,
    bool    _redemptionShield    // true = enable Redemption Shield at open
)

Opens a trove at ≥ 2,000 RD total debt (_RDAmount net + 200 RD gas reserve). Mints _RDAmount to the caller and 200 RD to the GasPool.

Reverts:

• "Resulting ICR < MCR" — ICR below the branch minimum.
• Normal mode: "BO: tcr<ccr" — the open would push branch TCR below CCR.
• Recovery mode (branch TCR already < CCR): "Resulting ICR < CCR" — a fresh open must reach ICR ≥ CCR.
• "Agg:issuanceQuota" — the branch issuance bucket is empty; retry after it refills (read Aggregator.issuanceQuotaAvailable(tm); mechanics in Rates vs. utilization).

Adjust

BorrowerOperations.adjustTrove(
    uint256 _collateralToAdd,
    uint256 _collWithdrawal,
    uint256 _RDChange,
    bool    _isDebtIncrease,
    bool    _toggleShield, // toggles Redemption Shield in the same tx
    address _upperHint,
    address _lowerHint
)

One direction per call for collateral (add or withdraw) and for debt (increase or repay). Every adjustment must end with ICR ≥ MCR, netDebt ≥ MIN_NET_DEBT (1,800 RD) unless closing, and no TCR drop into recovery.

Convenience wrappers

Thin calls into the same accounting — pick whichever matches intent.

Op	Entry point	What it does
Top up collateral	addColl(amount, upper, lower)	Pulls more collateral into your trove
Withdraw collateral	withdrawColl(amount, upper, lower)	Sends collateral back (must keep ICR ≥ MCR)
Borrow more RD	withdrawRD(amount, upper, lower)	Mints more RD, increases debt
Repay RD	repayRD(amount, upper, lower)	Burns RD from your wallet, decreases debt
Enable Redemption Shield	shieldTrove(upper, lower)	Migrates the trove to the Redemption Shield cohort
Disable Redemption Shield	unShieldTrove(upper, lower)	Migrates the trove back to the base
Close trove	closeTrove()	Burns full debt, returns all collateral, refunds the 200 RD reserve
Claim post-redemption/liquidation surplus	claimCollateral()	Pulls any collateral surplus owed from CollSurplusPool

closeTrove() requires the caller to hold enough RD to cover the full debt (net + accrued interest); the protocol won't close while net debt remains.

Shield toggle cooldown

The Redemption Shield setting changes through shieldTrove / unShieldTrove (or adjustTrove(..., _toggleShield: true, ...)). Read the current setting with TroveManager.shielded(borrower). BorrowerOperations enforces SHIELD_TOGGLE_WAIT = 86400 seconds (24 hours): after any setting change — including the choice made at open — another change reverts until 24 hours elapse. The clock is per borrower and resets on each change.

Also on BorrowerOperations

• moveCollateralGainToTrove(_user, _coll, _upperHint, _lowerHint) — route a Stability-Pool collateral gain straight into your trove on the same branch. See Earning.
• forceCloseTrove(address) — clean up an undersized "dwarf" trove for a bounty. See Liquidation & cleanup.
• shutdown() / shutdownFromOracleFailure() — branch shutdown triggers. See Redemption.